Noob gearing question

nannerby

Probably a silly question but I got a new bike 11 speed and the gearing is 50*34 I find it great going uphill no probs at all but when im on the flat I find that to keep up with the group I need to go into the big ring and big gear and even then im struggling for speed,do I need to change the cassette or something else?

Cee-Jay-Cee

nannerby wrote: »

Probably a silly question but I got a new bike 11 speed and the gearing is 50*34 I find it great going uphill no probs at all but when im on the flat I find that to keep up with the group I need to go into the big ring and big gear and even then im struggling for speed,do I need to change the cassette or something else?

So on the smallest cog on the rear and large front ring your spinning out?

If that is the case then you need to change your front chainrings to a standard 53/39 set up.

Wishbone Ash

Presumably your highest gear is either a 50/11 or a 50/12. Unless you're out with semi pro riders, it puzzling how that is too low.

Are you sure you are using the largest gear - i.e. smallest cog on rear - big ring up front?

nannerby

Yes big front ring small rear cog..its not that im spinning out im doing about 90rpm but if I was to shift up a gear or two I feel would start spinning out.
Just checked its 50/12.

T-Maxx

Did a quick calc and you must be doing about 50km/h then.

endacl

Are your wheels too small?

Wishbone Ash

nannerby wrote: »

Yes big front ring small rear cog..its not that im spinning out im doing about 90rpm but if I was to shift up a gear or two I feel would start spinning out.
Just checked its 50/12.

A 50/11 will give you a little bit more.

Why would you shift up a gear or two if it would cause you to spin out?

Most of us only spin out on a long shallow descent on a good surface with no potential hazards and it's usually only for a minute or less.

If you're spinning out on the flat, you must be really 'trucking' along.

tuxy

T-Maxx wrote: »

Did a quick calc and you must be doing about 50km/h then.

51.87 km/h at 90 RPM to be exact
How long does this group hold that speed for? :eek:

nannerby

tuxy wrote: »

51.87 km/h at 90 RPM to be exact
How long does this group hold that speed for? :eek:

That's the problem lol im doing the 90rpm but not getting the speed maybe im wrong about the gears il check them again or could it be something else?

ED E

Are you very short OP? (as in is this an XS bike)

650c would throw those calcs a bit.

nannerby

Its size small lapierre.

tuxy

nannerby wrote: »

Its size small lapierre.

And you're sure you have a 50 big ring on the front? What size is your smallest cog on the back?

ED E

tuxy wrote: »

51.87 km/h at 90 RPM to be exact
How long does this group hold that speed for? :eek:

Is that right?


90 RPM, 25mm tyres, 700c, 50 x 12 = 47.54kmh
90 RPM, 25mm tyres, 650c, 50 x 12 = 43.93kmh by bikecalc.com

Its a delta but 44km/h is still fast enough...

tuxy

I used this bikecalc.com, perhaps I made a mistake?
I don't think we know what small cog he has. But 11 seems to be standard for most bikes that are 11 speed.

nannerby

tuxy wrote: »

And you're sure you have a 50 big ring on the front? What size is your smallest cog on the back?

yes just checked again 50 and 12 at the back.

tuxy

nannerby wrote: »

yes just checked again 50 and 12 at the back.

Ed E's calculation of for 47.54kmh at 90 RPM should be correct then.

Are you sure it's shifting into the 12 cog?

ED E

tuxy wrote: »

I don't think we know what small cog he has.

I was going on 12 as per post 4 which they've just confirmed.

nannerby

tuxy wrote: »

Ed E's calculation of for 47.54kmh at 90 RPM should be correct then.

Are you sure it's shifting into the 12 cog?

Tbh I just assumed it was..im out on it later and will make sure.

tuxy

nannerby wrote: »

Tbh I just assumed it was..im out on it later and will make sure.

Do you have any strava rides logged with the group? We could see if you have the wrong gearing based on that.

TGD

Or learn yo spin at 100rpm for short periods

Cee-Jay-Cee

nannerby wrote: »

Yes big front ring small rear cog..its not that im spinning out im doing about 90rpm but if I was to shift up a gear or two I feel would start spinning out.
Just checked its 50/12.

If your not spinning out then there is no problem, you have a problem when you are in the 50/12 combo and can’t spin your legs fast enough to keep up with the speed and therefore need another gear. Until that starts happening then you don’t need to do anything.

On a side note do you live in Holland or somewhere very flat? I’ve been cycling approx 8 years now and I can count on one hand the number of times I’ve been in the 50/11 and spun out.

eeeee

OP 90rpm isn't near spinning out. I race on a compact, 50x34, and I've never wanted for gears, either racing or training. I've friends A2 that race on a compact too.
You need to work on your cadence, 90rpm is not fast by any measure. Everyone is different, but 90 is a resting cadence.

Work on your cadence, get a block with an 11 on it if you want, 50x11 is bigger than a 53x12.

But 90 is really not spinning out.

Cee-Jay-Cee

Cee-Jay-Cee wrote: »

So on the smallest cog on the rear and large front ring your spinning out?

If that is the case then you need to change your front chainrings to a standard 53/39 set up.

Are you for real.........