changing from 32 to 36tooth crank

[kcarbon]

hi all just got LBS to fit a 36tooth crank , also service check stock chain for stretch or wear, take another 5psi air pressure out front fork.
bike has 2,140k's and original chain checked out ok. I always regularly oil with Rock N roll Gold. never use water to clean just clean rag & tooth brush.
also when picked up bike I road it in car park then they had a brand new stock FSR levo mine felt faster, the service guy road the two bikes an agreed. but wait till I get it out it real world & report back.

 

[kcarbon]

Well I have ridden 100k with the 36t crank, love it! used it on paved and rough dirt track. I'm faster , as time myself most rides I do and have cut trip times down. was mostly using 20% eco, battery range same.

 

[Varaxis]

36t front ring, 10t rear cog, 165mm crank, 27.5x2.8 tire? How fast you going? On eco too?

I outpace my pedal-assist restriction (US 20 MPH) with 34x13 with 175mm and 27.5x2.8 tire at 85 rpm. I'm fit enough to only need eco to reach the restriction, but maintaining that speed fully under my own power is another story. You can still go 25% faster than me in your higher gear at the same cadence.

 

[kcarbon]

36t front ring, 10t rear cog, 165mm crank, 27.5x2.8 tire? How fast you going? On eco too?

I outpace my pedal-assist restriction (US 20 MPH) with 34x13 with 175mm and 27.5x2.8 tire at 85 rpm. I'm fit enough to only need eco to reach the restriction, but maintaining that speed fully under my own power is another story. You can still go 25% faster than me in your higher gear at the same cadence.

Hi Varaxis, I'm no superman!!
it is very hard to explain , like as with most things that move, you can work it all out on a computer. then go out and try it & you will feel once you start peddling if you gained or lost or no different.
I already had a good idea this worked, as a close friend who also has a levo & no fitter than I am & same age +2. we mostly ride with the fast group. so we push ourself a bit. also we like to do a bit extra to the group ( might be cause we feel bad only E bikes? ) so we have planed meeting places & start times twice a week to meet the group. And we always pre plan a spot about 10k from meeting place. So we park and ride to meet. two Levo's two old age fellows ( I'm 69 friend 71 ) only difference is mine had 32T his has 36T, I would be peddling my heart out & my friend would be pulling away, this is on flat paved road, both over the motor I think I was doing 32kph myself motor power to 24kph. after 10k he would be a good distance ahead. but once on the dirt tracks no difference between us but a few times on smooth dirt tracks he has pulled away. he has had the 36T for 6 months.
I needed my next service so asked LBS to get and fit a 36T. they had a new levo fsr like mine young fit bike tech took mine for a test then the new one then we road together then we swapped bikes. I could feel mine was noticeably faster we were on paved car park flat level. the tech said mine felt faster to him too.
but next week with the group I'll really know how much difference.
also my bike came with the 27.5" x 2.8" butcher, but I noticed they did not roll as well as my last levo ( had two ) the first levo had 27.5" x 3.0". I had two spare new tyres from that, so went tubeless & fitted the 27.5" x 3.0" it rolls much better, the tyres flex a bit but nice smooth ride. that's my story. I'll put it on mission control & ride over same road I have ridden before & think I still have the ride stored in MC. so can compare, will do that maybe tomorrow.

 

[Varaxis]

Oh, I didn't expect you to credit the efficiency gains to the chainring alone. Bigger sized cogs/rings in general are more efficient and a bigger chainring reduces anti-squat on FS bikes. Anti-squat converts chain tension into a force that extends your swingarm, to keep the rear high in its travel and counter the sagging under power feeling. Less of it means more chain tension goes into turning the rear wheel, but may require a bit more damping to achieve desirable ride stability.

Interesting upgrade. Nice that you had someone else confirm, else I would've suspected placebo, just cause I didn't expect it to be so significant. Figured there had to be something else, like worn tires, broken in bearings, better maintenance habits, better lubrication, or something. xD

 

[kcarbon]

Oh, I didn't expect you to credit the efficiency gains to the chainring alone. Bigger sized cogs/rings in general are more efficient and a bigger chainring reduces anti-squat on FS bikes. Anti-squat converts chain tension into a force that extends your swingarm, to keep the rear high in its travel and counter the sagging under power feeling. Less of it means more chain tension goes into turning the rear wheel, but may require a bit more damping to achieve desirable ride stability.

Interesting upgrade. Nice that you had someone else confirm, else I would've suspected placebo, just cause I didn't expect it to be so significant. Figured there had to be something else, like worn tires, broken in bearings, better maintenance habits, better lubrication, or something. xD

Thanks for your input, I just did a ride that covers 20km I managed to beat my best average by 5kph, so something is working. but like someone else mentioned, I suppose it is the type of riding. I don't seem to get much single track technical type riding. mostly dirt tracks lot of hills. I have ridden it 2,200km total now. I enjoy it!

 

[caterhamnut]

Interesting - I get frustrated at how quickly my legs are spinning when I am on the road, so have been wondering about increasing the size on the front - thats only mainly riding 'to' the trails, or on the roads in-between, so I still want the low gearing for those rocky climbs we have here on Dartmoor...I wonder if going up to 34t will be a compromise, or will it hardly be noticeable?

 

[ccrdave]

Im very interested in this but fitting a bigger front ring will just move the gearing up a cog or two wont it. As i see it the only benifit is if you are spinning out on the current gearing, is that right?

 

[caterhamnut]

correct Dave - I am spinning out too quickly with the 32t on the Levo

 

[kcarbon]

I suppose it would be individual requirement. like this is a mass production, so one fit's all.
like caterhamnut, I noticed I'm spinning out. But when I'm going up steep dirt tracks I was never using the largest gears on rear cluster. I also notice I now use the smallest gear on rear cluster & I have also used the largest for the fist time since owning this bike. I have not had a problem via gear ratio & seem to have more use of the full cluster.
my friend with a 2017 Levo changed to the 36tooth 6 months ago & has said he would like to try 38.
for me it seems like a positive move.
I think your riding environment & your body weight, I'm 74kg ( but ideal 69kg ) my friend is 95kg.
I think if you are not sure & ride over large rocks , you could try 34t.

 

[kcarbon]

Update, just got home from first group ride with the 36 tooth front Sproket . I can now report noticeable gain!
was a 41k ride weather was about 25c sunny. some big long climbs mostly dirt roads but some paved. these guys ride hard I could never beat them on a flat or down hill as they all have taller gearing non E mountain bikes some full carbon Specilized. but now with 36 t on crank after 23k I stopped waited for them they took 4 min to get there. then we had some big hill's then some fast downhill . I completed the rest of the ride then waited 15minutes for them at a cafe. one bike was also a Levo. I got to 78kph on the downhill. I would not go back to 32 tooth!!