E180RS ....shorter cranks.

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,105
4,636
Weymouth
I guess the Hope 155mm cranks have persuaded quite a few Whyte owners to change cranks....primarily to reduce pedal strikes.
I stopped getting pedal strikes on my E180 once I learned to read the trail but it still does mean having to put in half pedal rotations more than I would like......so I became curious.
I have no such issues with the e160RSX.....both bikes have 165mm cranks....but the RSX is 29er which probably accounts for the difference.
So 155mm cranks for the E180 looked a worthwhile experiment......that is until I did more research!
Firstly the Hope cranks are too expensive for an experiment and I doubt they are any better than Praxis or Race Face Affect which are considerably cheaper.
Secondly for every 5mm cranks length reduction you really need to reduce the chainwheel by one size to maintain the same gearing.
Thirdly the shorter the crank the more power you have to input to get the same result in terms of trail progress/speed and pedalling efficiency is already not a strong point on the E180.
Lastly 10 mm is huge reduction when you consider what a 20mm diameter reduction means in terms pedal rotation circumference and that in turn impacts on weight distribution and balance when stood on level pedals.
So my conclusions are to try 160mm cranks probably by Race Face or Praxis , keep the same chainwheel and accept that I will need to be in 1 lower gear most of the time.
 

Bomble

Well-known member
Subscriber
Nov 11, 2018
646
380
Yorkshire
I’ve put 155 on my 160 and after a few minutes I couldn’t tell the difference😀 Soon get used to them.
 

Bomble

Well-known member
Subscriber
Nov 11, 2018
646
380
Yorkshire
I’ve just mulletted my Rsx too, so I’ll see if that makes any difference. Though if you believe the figures on the Whyte site, the mullet bikes have a higher bb than the 29😀
 

Jag009

New Member
Sep 9, 2022
106
57
Loch lomond
I’ve just mulletted my Rsx too, so I’ll see if that makes any difference. Though if you believe the figures on the Whyte site, the mullet bikes have a higher bb than the 29😀
really interested to see how you get on with the mullet ,i was thinking of doing mine , did you change the pivot point on the rear shock or leave the same as the 29 "
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,105
4,636
Weymouth
Can you explain this

Can you explain this please?
Consider the difference a longer bar makes to loosening a bolt....ie rotating it. The longer the lever the less effort you have to apply. The shorter the lever the more effort. It is the same with a crank. The longer it is the less rider input is required to turn the chainwheel in any given gear. More rider input is required if the crank is shorter. To equalise the rider effort a lower gearing is required. Emtbs invariably have lower bb because of the positioning of the motor so 165mm cranks were fitted more often than the previous 170mm/175mm norm.....but the motor assistance helped negate the additional input required....plus 12 speed gearing and smaller chainwheels.
 

Doomanic

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Jan 21, 2018
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Yeah, I understand all that. Changing crank length does not itself alter gearing, but may require a change to retain the perceived effort.
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,105
4,636
Weymouth
Yeah, I understand all that. Changing crank length does not itself alter gearing, but may require a change to retain the perceived effort.
yes, by "gearing" I was referring to the percieved effort............ie what gear it feels like ...sorry if that was confused.
 

Clubby

Active member
Oct 3, 2020
159
132
Tayside
Sorry Mikerb but I’m calling bollocks on all the perceived effort nonsense. Back in my singlespeed days I changed from 180mm to 170mm and noticed no difference. I’m also running 155mm Hopes and notice no difference in the gears I’m using. Huge reduction in the number of pedal strikes on my gen 1 rs150.

Yes there’s a reduction in lever length but add in the length of your leg and it’s not as big a percent as you think.
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,105
4,636
Weymouth
Sorry Mikerb but I’m calling bollocks on all the perceived effort nonsense. Back in my singlespeed days I changed from 180mm to 170mm and noticed no difference. I’m also running 155mm Hopes and notice no difference in the gears I’m using. Huge reduction in the number of pedal strikes on my gen 1 rs150.

Yes there’s a reduction in lever length but add in the length of your leg and it’s not as big a percent as you think.
I am happy you are pleased with the change you made but that may not be the case on a different bike. A 5mm reduction in crank length translates to a reduction the circle circumference they create of over 31mm, meanwhile your leg length is not part of the lever.........only your leg extension, and that is reduced. Of course a lot does depend on the the starting point in terms of chainwheel diameter and gear ratios on the cassette on any particular bike such that crank length reduction may or may or not be that noticeable.
 

BeBiker

Active member
Aug 26, 2020
655
403
Belgium
I went from 165mm to 160mm to avoid pedal strikes.

Didn't like it, and after a few rides I changed it back.
 

Clubby

Active member
Oct 3, 2020
159
132
Tayside
Power is equal to torque x speed.
Shorter cranks are theoretically easier to spin faster, although I know on my Bosch if you spin too fast the assistance definitely tails off.
On an ebike you have an easily accessible 85Nm of torque which depends very little on the strength of the rider. I just think it’s a non issue within the narrow range of cranks lengths available.
Feel is a different matter and all about personal preferences.
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
6,105
4,636
Weymouth
Interesting article but obviously mostly about road cycling. Something similar but focused on emtbs would be good. We have lower bbs, a motor, and when seated adopt a more upright position on the bike.......many of us also spend a lot of time standing on the platform provided by the cranks. So a lot of differences. A relevant point was made in the article about steeper seat tube angles and that is a feature on quite a few of the latest emtbs but mostly only talked about in terms of better climbing rather than its impact on power through the cranks.
 

Jag009

New Member
Sep 9, 2022
106
57
Loch lomond
Interesting article but obviously mostly about road cycling. Something similar but focused on emtbs would be good. We have lower bbs, a motor, and when seated adopt a more upright position on the bike.......many of us also spend a lot of time standing on the platform provided by the cranks. So a lot of differences. A relevant point was made in the article about steeper seat tube angles and that is a feature on quite a few of the latest emtbs but mostly only talked about in terms of better climbing rather than its impact on power through the cranks.
Have a look at this
 

Walkea

Member
Aug 18, 2019
64
39
Glasgow
Have a look at this
Don't follow embn. On the odd occasion I have watched the channel most of the videos seem full of fluff and very little real content. However I liked this video because it is a subject I was researching.
What would be interesting is a follow up video testing crank length on more varied UK type terrain as 165 to 150 maybe too much of a difference but 165 to 155 may be more of a sweet spot.
Thanks for posting it.
 

Jag009

New Member
Sep 9, 2022
106
57
Loch lomond
Don't follow embn. On the odd occasion I have watched the channel most of the videos seem full of fluff and very little real content. However I liked this video because it is a subject I was researching.
What would be interesting is a follow up video testing crank length on more varied UK type terrain as 165 to 150 maybe too much of a difference but 165 to 155 may be more of a sweet spot.
Thanks for posting it.
I have been toying with the idea of going from 165 to 155 myself , so have been researching and asking fellow riders ,most have said 155 are the way to go , now just need to see what ones to go for and how much i want to spend
 

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