Fixed gear ratio - Advise please.

All My Stars Aligned

Hey all,

I'm hoping someone can advise me on the gearing of my Dolan fixed gear.

I'm currently running 49/15 ratio however I'm keen to lower this as I've picked up a slight knee problem and feel a easier gear would help. I also fancy spinning more rather then grinding!

I'm wondering would I be best to swap out the chainring for something like a 46 of should I change to a larger sprocket at the back?

All advice appreciated.

Cheers.

Beasty

49:15 is the sort of gearing used for racers on the track. Indeed at the likes of Manchester Velodrome that's the maximum you are allowed in public sessions and their hire bikes are quite a bit lower. Taking into account inclines and all the starting and stopping, 49:15 seems incredibly high gearing unless you're training for something like the track nationals. Otherwise I would suggest as a minimum changing your rear cog to a 16.

All My Stars Aligned

Thanks Beasty. The bike is a track bike that I used to be used for racing (not by me tho') Would moving to a 16 tooth make much of a difference?

Beasty

One on the back is worth over 3 on the front at that ratio, so yes it will make a difference, but equally you could also swap the front for a 46 or 47 and that would improve it further

magicbastarder

what do you use the bike for? generally when i'm on the flat, i stick to a 39-15 (or sometimes 16) ratio, so the one you mention would be a tough one for me.

C3PO

I use 44-16 on my SS commuter and find it a good compromise for a fairly flat 15km commute with a few short climbs!

Harrybelafonte

49x17 is still too big. In fact, if you've got a knee lroblem, I'd recommend considering going single speed or geared. Dear braking on fixed will damage knees too?

All My Stars Aligned

Generally a flat 45min commute.

CramCycle

You also have to account for the range of your chain, depending on where your rear wheel is sitting at the minute, if you increase the rear too much, you may have to decrease the front anyway to make room (or get a new chain). With the issues on your knee, as harry pointed out, do you have proper brakes set up, and would going single speed help ease issues? I'd consider changing both if you have the budget.

All My Stars Aligned

@harry, I take your point about going single speed. I tend to do the majority of my breaking using a combination of cycling at an appropriate speed, watching whats ahead and using my front break (I'm far too old for skid stoping!). That said, there is always an element of using my weight/resistance against the cranks I guess. Unfortunately the bridge on the rear isn't drilled for a break and I'm not in a position to replace the frame right now.

All My Stars Aligned

@cramcycle the rear wheel is sitting about 3/4 of the way back in the dropouts. The chain is about as very little slack. The chain is only a few weeks old and I kept the extra links I didn't use when fitting so I'd hope to be able to adjust it either way as needed.

Wishbone Ash

I think mine is a 48/17. My previous set-up was a 48/16 and was therefore 3:1 so the present one is slightly less. Spin out a bit on the flat with a strong tailwind but otherwise fine.

Harrybelafonte

All My Stars Aligned wrote: »

@harry, I take your point about going single speed. I tend to do the majority of my breaking using a combination of cycling at an appropriate speed, watching whats ahead and using my front break (I'm far too old for skid stoping!). That said, there is always an element of using my weight/resistance against the cranks I guess. Unfortunately the bridge on the rear isn't drilled for a break and I'm not in a position to replace the frame right now.

Ok, cool. Tbh, everyone here is gonna ride different gearing. I rode around on a 49x17 and my route is not flat. I use 49x19 now I think. You can see the variance in gearings mentioned by all here so far. We're all different ages and different strengths.

I would personally recommend you buy a new decent and cheap KMC chain. Get a decent or second hand 46 chainring for your 15 and if that still cause problems go for a 16. Just make sure you leave space on your chain to accommodate the bigger gear at the back when you're sizing the chain.

This might help re gearing:

CramCycle

All My Stars Aligned wrote: »

@cramcycle the rear wheel is sitting about 3/4 of the way back in the dropouts. The chain is about as very little slack. The chain is only a few weeks old and I kept the extra links I didn't use when fitting so I'd hope to be able to adjust it either way as needed.

The definitely increase the rear cog. You might squeeze in an 18 but at least go for a 17. As you can see from the replies here, everyone's optimal gear is different, tyre size alone can make a difference.

The one thing I noticed on your OP is that you picked up a knee problem, so where you OK with the gear you had or did that help inflict the issue? Are your cleats set up right, is your saddle too high or too low, is your handlebar at a comfortable distance? I used to spin stupidly high gears commuting, still do actually but 46 x 16 to me is a nice all rounder (currently running 49 x 15 like you), you should get up most hills, keep a decent pace on the flat, be able to deal comfortably with head wind. You will spin out on down hills but sin e.

piston

Use a gear somewhere between 63 - 67 gear inches for general riding. That's the traditional winter training gear. Anything much higher is for time trials.

C3PO

piston wrote: »

Use a gear somewhere between 63 - 67 gear inches for general riding. That's the traditional winter training gear. Anything much higher is for time trials.

Which puts my 16/44 right at the top end - personally wouldn't want to be pushing anymore into recent headwinds on the N11!!

All My Stars Aligned

Thanks all for your advice, very much appreciated.

Had an MRI and since seen a knee specialist in the Sports Surgery Clinic and he's advised surgery (as surgeons do). Waiting on a date, oh joy!!!

As for the bike, I've ordered a 46 chainring and a 16 & 17 sprocket. Will be a while before I get to try them out.

Again thanks for all the pointers.