Can anyone advise me-breaking rear axle

Robertd_07

Hoping someone can offer an opinion/guidance.
I cycle a 25km commute every day on a Trek 4100 (mountain bike)
Been at it regurlarly since Feb.
Broke my first rear axle in early April.
Now just realise my 3rd one is gone.
So that's 3 axles in 3 months! (Although I blame one of those on a bike shop in town who I think over-tightened the axle.)
A reputable LBS in west Dublin recommend a new rear wheel, with a newer style hub (cones much further out, rather than at the hub-reduces torsion on axle) at a cost 70-90 for wheel, cassette & chain.
Thoughts anyone.
Robert

irishmotorist

I don't think I've ever broken a rear axle, so it sounds strange to me. Whereabouts and how is the axle breaking? Do you have a tendancy to go bouncing straight into kerbs at high speed?

Dr_Colossus

It happens every so often especially on the older style hub with a freewheel where the axel cone is quite a long way in from the frame. This puts more pressure on the axel especially when cycling on the small gear of the freewheel. I've broken an axel and bent another in my time but think you're very unlucky to break 3 in 3 months, could be a faulty or cheap axel. Do you cycle up a few steap hills riding out of the saddle with a lot of side movement on the bike as you're pushing the pedals, this riding style will put additional pressure on the axel.
Also if the bike shop fitted the axle too loose it provides too much play therefore sudden bursts of power can cause the axel to jerk and snap. Having said that I'd prefer the axel a fraction too loose than too tight because when it's too tight it puts alot of pressure on your bearings and cups and can sometimes cause the cups to crack which then requires a new wheel.
Unless your freewheel and chain is very worn and possibly in need of replacement anyway I don't think a new wheel, cassette and chain is worth the money. I'd just ask the bike shop to install or order a good quality axle and just hope the previous one or two were just of poor quality or had some stress fracture

kona

Dr_Colossus wrote: »

Unless your freewheel and chain is very worn and possibly in need of replacement anyway I don't think a new wheel, cassette and chain is worth the money. I'd just ask the bike shop to install or order a good quality axle and just hope the previous one or two were just of poor quality or had some stress fracture

3 axles in 3 months? Id say replace the wheel, it sounds to me like the hub is just ****e.
Definatley replace the wheel IMO, your just gong to keep snapping axles and paying more and more money.
The chain also defo needs replacing 25k a day since febuary? definatley new chain and cassette time.

Now e90 seems VERY cheap, too cheap for a quality wheel chain and cassette IMO. then labour to change it all over and adjust the gears.

How old is your bike the last trek 4100 models are 2004. They are quite cheap, so id say its just poor parts causing your issues. Definatley follow the bike shops advice.

Why your axles are breaking? id say a bike shop fitted it to a worn hub, which caused it to snap.

Robertd_07

Do you have a tendancy to go bouncing straight into kerbs at high speed?

You'd think so, but no.

It happens every so often especially on the older style hub with a freewheel where the axel cone is quite a long way in from the frame. This puts more pressure on the axel especially when cycling on the small gear of the freewheel.

That's what I'd say is the problem. Cycling a mtb, with mtb gearing, on a commute, I don't ususall go below the 5 sprocket on a 7 sprocket cassette.

I'd just ask the bike shop to install or order a good quality axle and just hope the previous one or two were just of poor quality or had some stress fracture

The thing is that it's a real inconvenience when it goes, last time it took me an hour and a half to walk home. I'm fairly good at putting new axles in now (used to happen when I was younger on a different bike) Also, as they're quick release, the skewer goes too, so it's €10-€15 each time.

Unless your freewheel and chain is very worn and possibly in need of replacement anyway I don't think a new wheel, cassette and chain is worth the money.

As far as I understand it, they can't just transfer my existing cassette, as it is an older, incompatible type. This would then necessitate a new chain.

I'm thinking I might just give a new axle a go for now, and see what happens considering the cost, although I've a feeling it'll be a false economy.

Anyone else with suggestions/thought?

kona

trek 4100 uses a 7 speed hg40. What they probably mean is that its real dificult to get 7speed freehubs any more, so they are putting on a freewheel.

Now they could just swap your freehub from your current wheel onto your new wheel.

Robertd_07

Thanks all.
I've now changed my mind again (thanks Kona)
Thinking that I'll just go and get the new wheel & cassette.
Forgot to mention that the rear wheel has been buckled, trued, buckle again, then popped a spoke. (The last time the axle broke was 2 days after the spoke was replaced-that's why I blame the bike shop)
Have to say though, looking forward to the new year, when I plan to get a new road bike. (Really annoyed at myself for not getting one this year-too late now unfortunatley)
Again, thanks to all.
Robert

Dr_Colossus

As far as I understand it, they can't just transfer my existing cassette, as it is an older, incompatible type. This would then necessitate a new chain.

Correct, what they've advocating is the newer hub design with a slip on cassette rather than the exisiting screw on freewheel. The newer hub design have the bearings and therefore pressure points out at the end of the axel near the frame so would be less inclined to bend and break under pressure. Generally a cassette have narrower gear spacings than a freewheel thus allowing up to 10 gears on the hub, as such the chain is generally of a thinner variety in the region of 11/128" and thiner as opposed to the standard 3/32". If you do go the route of changing your wheel and cassette then make sure the new chain is compatible with your derailleur and crankset and definately not worth replacing everything, easier and probably cheaper to buy a new bike

DePurpereWolf

Quick release wheels have hollow axel's (I believe) I've broken my axel once as well, I just got a new wheel, same 7-speed freewheel hub.
I would have done it myself but couldn't really find anything cheap, the shop did it for me for like 75 euro or something. The cheapest wheel I could find was near 100 euro.

My wife's bike is not a quick release and I was fixing that up yesterday, that axel is just a solid ~1cm diameter rod.

I would get a new (second hand) bike if your axel keeps braking. Try to get one without quick release (although it shouldn't matter, all road cycles are quick release and they don't have that problem).

kona

Dr_Colossus wrote: »

As far as I understand it, they can't just transfer my existing cassette, as it is an older, incompatible type. This would then necessitate a new chain.

Correct, what they've advocating is the newer hub design with a slip on cassette rather than the exisiting screw on freewheel. The newer hub design have the bearings and therefore pressure points out at the end of the axel near the frame so would be less inclined to bend and break under pressure. Generally a cassette have narrower gear spacings than a freewheel thus allowing up to 10 gears on the hub, as such the chain is generally of a thinner variety in the region of 11/128" and thiner as opposed to the standard 3/32". If you do go the route of changing your wheel and cassette then make sure the new chain is compatible with your derailleur and crankset and definately not worth replacing everything, easier and probably cheaper to buy a new bike

The 4100 has a cassette as standard anyways. It also has shimano acera and suntour cranks.Its going to be perfectly compatible. The rear wheel is popping spokes and snapping axles because its ****, even as a freehub design.
The bike shop are just reccomending getting better quality parts(i hope at e90 all in it sounds a bit too cheap)

kona

DePurpereWolf wrote: »

I would get a new (second hand) bike if your axel keeps braking. Try to get one without quick release (although it shouldn't matter, all road cycles are quick release and they don't have that problem).

why the hell would you buy a new bike if a axle keeps breaking? QR is a far better system than a bolt on axle.

Gurgle

Replace the axle with a stainless steel threaded bar.
Won't break so easy.

Robertd_07

As a bit of background, I'm a Civil Engineer, so would have a baisc understanding of the mechanics of the forces in play in the rear wheel.
Thing is, I can't help thinking that it's something I'm doing wrong, either in my cycling, maybe some other way.
I don't think that I'm too heavy for the bike (less than 100kg), and I thought Trek/Bontrager were reasonably reliable, so other than that, I've no idea what's going on.
It's not like my bike is subject to greater stresses than other people who cycle to work on MTB's. (Or masochist as I was called on Friday in the bike shop)

For peace of mind, and reliability I'll probably go with a new rear wheel etc. but would really love to know why this happened.
Does it happen to other people regurlarly or did I just get dodgy axles?

kona

Robertd_07 wrote: »

As a bit of background, I'm a Civil Engineer, so would have a baisc understanding of the mechanics of the forces in play in the rear wheel.
Thing is, I can't help thinking that it's something I'm doing wrong, either in my cycling, maybe some other way.
I don't think that I'm too heavy for the bike (less than 100kg), and I thought Trek/Bontrager were reasonably reliable, so other than that, I've no idea what's going on.
It's not like my bike is subject to greater stresses than other people who cycle to work on MTB's. (Or masochist as I was called on Friday in the bike shop)

For peace of mind, and reliability I'll probably go with a new rear wheel etc. but would really love to know why this happened.
Does it happen to other people regurlarly or did I just get dodgy axles?

well, the forces on the axle are compression from the frame, and tension when you tighten the bolts. All works fine if everything is in order, and straight, and tightened correctley.
When you snap a axle somthing has obviously been exposed to forces above what its designed for. Considering that the axle is high tensile steel, Tightening the axle nuts too much puts the axle under too much tension, then the compression does the rest IMO.

Then once this happens there is always damage to the hub as its softer than the axle/cones/bearings. This throws everything out, as the wheel in some cases doesnt run smooth, which causes a high load to be concentrated on a particular area. Again snap.
If the wheel isnt centred in the frame, the load on the axle is off centre, again snap.

This is the way I see it, I'm sure there is studies into it with maths and the like.

Bontrager make some really **** parts, matrix rims wouldnt be the best either. Replace the wheel with somthing decent, the shimano m475 rear hub is quite strong, rimwise, alex rims are cheap and strong, some DT swiss spokes would make the wheel quite durable.

tomasrojo

I've broken the rear axle twice on my soon-to-be-retired hybrid, but the breaks were much futher apart in time than what the original poster is suffering. Mine were well over a year apart. My wheels use the old-style screw-on freewheel, which as Dr_Colossus mentions, is a weaker design than the newer freehub design. The axles were the solid type rather than the hollow quick-release type; still doesn't stop them breaking the odd time.

Húrin

Gurgle wrote: »

Replace the axle with a stainless steel threaded bar.
Won't break so easy.

The threads on most threaded bar are slightly different in TPI to the threads on cone nuts.

kona

Húrin wrote: »

The threads on most threaded bar are slightly different in TPI to the threads on cone nuts.

just tap your own to the correct size.

DePurpereWolf

When overhauling a quick release axle you need to be careful of not overtightening it. Because when you put it on the bike you tighten it even further. So you have to check the play in the axle when the wheel is on the bike.

Maybe Kona could enlighten me why a quick release axle is much better than a normal one.

bonham23

i had the same issue with a trek 3500 .. the axle snapped and i replaced it but it was never 100% after that so i replaced the rear wheel. I got a custom wheel made up on chanreaction with a new casette. My trek used the older freewheel style cog so i couldn't reuse . using advise from boards members i got a custom mavic 337 rim with a shimano deore hub and shimano hyperglide casette for less than 90 euro if memory serves correctly. i also has a tenner discount from crc though.

DePurpereWolf

After reading this thread I got nervous and started checking by rear wheel. I do believe that my rear hub is shot again. Just as the post starter.
The bike rides, but I'm afraid if I try to overhaul the rear hub I won't be able to put it back together.
This rear hub was overhauled only 3 months ago by a mechanic.
I'll be following bonham's advise and get me a new wheel.

BostonB

DePurpereWolf wrote: »

...Maybe Kona could enlighten me why a quick release axle is much better than a normal one.

Wondering that too.

Often thought about replacing QR with non QR for security. Mind you it would still be the same axel. Different nuts etc.

Gavin

There doesn't happen to be a loose ball bearing lost in the hub perhaps ? This can grind the **** out of an axle, cut a deep groove into it, enough to weaken it.

kona

DePurpereWolf wrote: »

Maybe Kona could enlighten me why a quick release axle is much better than a normal one.

Because it stops you having to lug around a 15mm spanner for a start.
Its quicker to remeove a QR wheel than with a bolt on axle.
They are lighter(for all you roadies;))
When used correctley they allow you to secure the wheel correctley close to perfect torque. Swinging out of a track nut wil make you **** up your hub(same for the geniouses who dont understand the principle of a lever and use a pliers to tighten the nut at the end of a QR skewer)

They are Almost* Idiot proof.

You will find it hard to put your QR wheel in crooked, with a track nut on a threaded axle its quite easy.

There is a few valid reasons off the top of my head. Although if you have a small clue about bikes you will just disregard them.


* nothing on a bike is idiot proof, alot of Idiots ride bikes, and try to fix them.

kona

DePurpereWolf wrote: »

After reading this thread I got nervous and started checking by rear wheel. I do believe that my rear hub is shot again. Just as the post starter.
The bike rides, but I'm afraid if I try to overhaul the rear hub I won't be able to put it back together.
This rear hub was overhauled only 3 months ago by a mechanic.
I'll be following bonham's advise and get me a new wheel.

You should check the cones a few weeks after a service to see if they are still well adjusted. A bike shop would tighten them back up FOC if you had the work done there.

How do you know its shot?

DePurpereWolf

I don't know if it is shot (completely) I do know that if I put much force on the pedals the wheel comes out of line slightly (1cm to the left). Like I'm pulling the wheel out of alignment by pulling at the chain.
It's not as when the cones are not thight, then you can twist the wheel without much force, the wheel is loose on it's axle. This happens with the front wheel sometimes and I have no issue with fixing that.
The wheel seems to be on pretty okay if you look at it at rest. There is not much play between axle and wheel.

I only know if the axle is shot if I open it up, I'd rather do that if I have a spare wheel laying around.

Robertd_07

Well, I got my bike back on Saturday after having a new rear wheel fitted, with new cassette & chain.
I never realised how bad the back wheel was until monday morning.
It's like a new bike.
Unfortunately, now that the rear wheel & gear change are so smooth, it's highlighted some further issues that need to be dealt with. (But they can wait a week or two.)
Robert

kona

DePurpereWolf wrote: »

I don't know if it is shot (completely) I do know that if I put much force on the pedals the wheel comes out of line slightly (1cm to the left). Like I'm pulling the wheel out of alignment by pulling at the chain.
It's not as when the cones are not thight, then you can twist the wheel without much force, the wheel is loose on it's axle. This happens with the front wheel sometimes and I have no issue with fixing that.
The wheel seems to be on pretty okay if you look at it at rest. There is not much play between axle and wheel.

I only know if the axle is shot if I open it up, I'd rather do that if I have a spare wheel laying around.

Do you have QR or a threaded axle?

Sounds to me like the wheel inst installed correctley.

What bike is it?

DePurpereWolf

It's a QR, I currently have a Victory 'handcrafted' hybrid. An old bike I want to keep around until I get my new one (stupid bike to work scheme)

I think it is installed incorrectly too, but if the bike mechanic doesn't know how to do it, I don't expect myself to be much better at it. These are things that only pop-up after some period of time so I can't really confront the mechanic with it. He would just say, it is a bad quallity wheel, which is correct.

The tyre is a 700Cx40, I have v-brakes.
I'm thinking of getting this wheel as replacement.
http://www.wiggle.co.uk/p/cycle/7/MWheel_Shimano_Deore~Mavic_A319_Rear_Wheel/5360035959/
Any thoughts?

tomasrojo

DePurpereWolf wrote: »

I don't know if it is shot (completely) I do know that if I put much force on the pedals the wheel comes out of line slightly (1cm to the left). Like I'm pulling the wheel out of alignment by pulling at the chain.

Is is possible that the right chainstay is cracked?

kona

DePurpereWolf wrote: »

It's a QR, I currently have a Victory 'handcrafted' hybrid. An old bike I want to keep around until I get my new one (stupid bike to work scheme)

I think it is installed incorrectly too, but if the bike mechanic doesn't know how to do it, I don't expect myself to be much better at it. These are things that only pop-up after some period of time so I can't really confront the mechanic with it. He would just say, it is a bad quallity wheel, which is correct.

The tyre is a 700Cx40, I have v-brakes.
I'm thinking of getting this wheel as replacement.
http://www.wiggle.co.uk/p/cycle/7/MWheel_Shimano_Deore~Mavic_A319_Rear_Wheel/5360035959/
Any thoughts?

Bring it to another shop, a bike mechanic should be able to install a wheel, or t least get to the bottom of the problem.

I wouldnt jump the gun with a new wheel, there are plenty of other things to rule out. The broken chainstay as mentioned is one. DAmage to the dropouts?, are the Track bolts worn? they have little teeth on them to stop the wheel moving.

DePurpereWolf

And the ballad continues.
I had gotten a new rear wheel installed by the local mechanic. Because I didn't specify and because we are dealing with a 7-speed bike, i don't think I got an expensive wheel, installation and all it was only 35 euro I think.
Anyway, I wasn't impressed by the installation because the wheel wasn't centered. It was straight in the frame, but too much to the right, so one of the brake pads would touch it much faster as the one on the other side. There wasn't any play and it ran pretty smooth.
But the wheel not being centred annoyed me so much that when I tried to replace the brake pads this week I ended up overhauling the whole rear hub.

And guess what?
My axle is bend again.

Cup and cones and bearings look okay.
I'd expect a 9mm thick solid axle would be the least of my worries.

kona

DePurpereWolf wrote: »

And the ballad continues.
I had gotten a new rear wheel installed by the local mechanic. Because I didn't specify and because we are dealing with a 7-speed bike, i don't think I got an expensive wheel, installation and all it was only 35 euro I think.
Anyway, I wasn't impressed by the installation because the wheel wasn't centered. It was straight in the frame, but too much to the right, so one of the brake pads would touch it much faster as the one on the other side. There wasn't any play and it ran pretty smooth.
But the wheel not being centred annoyed me so much that when I tried to replace the brake pads this week I ended up overhauling the whole rear hub.

And guess what?
My axle is bend again.

Cup and cones and bearings look okay.
I'd expect a 9mm thick solid axle would be the least of my worries.

Sounds like your mechanic is a bit half arsed. Although a new wheel and fitting for e35 is unbelievably cheap!

The reason that it was sitting off was because the spacing on the cones was off, if you look at two different wheels you will notice that they may have a different spacing going on. He should have copped this when he re-adjusted your brakes(He had to undo them to get the wheel out).

Id guess the wheel is ****, so the axle is very soft. Go for a decent wheel. CRC will build you up a cheap wheel with a shimano M475 hub.

DePurpereWolf

kona wrote: »

Sounds like your mechanic is a bit half arsed. Although a new wheel and fitting for e35 is unbelievably cheap!

The reason that it was sitting off was because the spacing on the cones was off,

But this should be the same for each wheel, unless the chain-stays are bend. But if the frame is perfect, the center of the wheel is always the same, in the centre of the hub, I mean, I hope we can assume that the spokes were the correct length and the centre of the rim is over the centre of the hub. If not, then the wheel is sh!te. If the frame is not perfect, it might be better to bend the frame than to change the spacers.

if you look at two different wheels you will notice that they may have a different spacing going on. He should have copped this when he re-adjusted your brakes(He had to undo them to get the wheel out).

Id guess the wheel is ****, so the axle is very soft. Go for a decent wheel. CRC will build you up a cheap wheel with a shimano M475 hub.

Well, this is the second shop that doesn't really care about the quality of their work. Don't get me wrong, if it was a E1000 bike I am convinced they would have done a much better job.

I'm one of those cyclists who likes tinkering with the bike better than riding. I live under the false assumptions that every bike can be fixed, by me.

I've put the wheel back in, it's rotating fine, it's only a slight bend and the wheel is maybe untrue for only 2mm. (the wobble would not be a result of the bend axle) I've looked at my frame and the chain stays don't look bend. I might use the 'wire' method to check more accurately.

If I go for a new wheel I might as well get a cassette hub. But then I'd have to get an 8speed cassette and change the shifter and maybe the rear derailer. It's a good thing the wife gave me a Park-tool workstand for christmas (no more back pain).

kona

The wheel may not be dished correctley either.

I bet its the spacing, just adust the cones until everything lines up. Or just measure how much its out by and ad a spacer. How are the gears? do they shift okay?

DePurpereWolf

It'll get me to work tomorrow, which is the sole purpous of this bike. I don't really know where to get a new rear axle from, the brand of the wheel is 'Quando'.

I'm going to order a complete new wheel set and build up new wheels from that. That'll give me a nice new project without much risk, if things go wrong, I'll just put the old wheels back.

With my new workstand and big blue book of bicycle repair (and this forum) I'm invincable.

kona

DePurpereWolf wrote: »

It'll get me to work tomorrow, which is the sole purpous of this bike. I don't really know where to get a new rear axle from, the brand of the wheel is 'Quando'.

I'm going to order a complete new wheel set and build up new wheels from that. That'll give me a nice new project without much risk, if things go wrong, I'll just put the old wheels back.

With my new workstand and big blue book of bicycle repair (and this forum) I'm invincable.

Ye quando are not the best.

keenclimber

I have a 2003 Trek 4100, and I've experienced multiple fractured axles. My last axle lasted only 2 hours before it was bent to the point that the wheel rubbed the frame. It's a bad design...my advice is to sell the bike and upgrade. Good Luck. Let me know if you find a fix.

kona

keenclimber wrote: »

I have a 2003 Trek 4100, and I've experienced multiple fractured axles. My last axle lasted only 2 hours before it was bent to the point that the wheel rubbed the frame. It's a bad design...my advice is to sell the bike and upgrade. Good Luck. Let me know if you find a fix.

What the hell were you doing!

Sounds liek your hubs was fecked to begin with!

DePurpereWolf

I bought new wheels for my crap bike, M:wheel deore/mavic wheelset from wiggle. Hasn't let me down yet.
Had to get a new cassette with it as well.

kona

DePurpereWolf wrote: »

I bought new wheels for my crap bike, M:wheel deore/mavic wheelset from wiggle. Hasn't let me down yet.
Had to get a new cassette with it as well.

Excellent choice

Ive deore hubs on alex rims on one bike, and Mavic crossrides and hubs on another. Both wheels just do what they are ment to with no fuss. Have the Mavics almost a year and a half and Ive never needed to true them or replace anything, and thats cycling on the "Notorious" dublin roads everyday.
Only thing I needed to to was to tighten the cones a tiny bit when I strip the bike down and rebuilt it.

best e130 Ive ever spent.

Wonder if people with BSO can count the amount they have spent fixing, truing and replaceing their crap wheels? bet its more than e130.