As expected, I’m getting loads of ground strikes on my new bike (Orbea Occam M10)
Not sure if it’s slightly different geometry to the alloy 2020 version that I test rode in the Lakes for three days or whether the Peak District ruts just make it feel worse.

Anyway, for some unfathomable reason the Muppets at the bike shop had specced it with 175mm cranks, which I’ll need to change to 170 or even 165mm

165mm seems like a step too far, just cos, but then searching older threads seems to suggest that there are actually a fair few people using them. So perhaps they might be worth a bash. If the worst comes to the worst then I guess I could put the 165s on the kid’s bike and nick his 170s for mine….

Anyway. Who uses 165s for long, long cycles? Are they ok?

Then pedals…. Currently got XT flats which are brilliant, but damn thick. Was looking at getting some Crank Bros Stamp 11s perhaps, which are 13/11/13mm if the bumph is to be believed. Could of course just get the Stamp 7s, but the idea of losing 50g off the heuge weight of the bike does appeal.

Any other suggestions for very thin, and indeed light, pedals?

If you are getting a lot of pedal strikes, that is more rider error than cranks that are too long. You need to anticipate the ground underneath you better and get the pedals out of harms way.

Loosing 50g in weight is not going to make any noticeable difference to the bike at all.

One-up pedals are a homage to the Gamut ones if being generous…. they’re pretty darn thin.

Weirdly I feel less of a difference switching deform 170 to 165 cranks and vice versa than I do 175 to 170 and back.
Choose to run 170, but would be perfectly happy on 165.

I’m running 165mm as I got a good deal on some DMR Axe cranks. Also wanted a bit more clearance and been very happy with them. You get used to them very quickly.

If you are getting a lot of pedal strikes, that is more rider error than cranks that are too long. You need to anticipate the ground underneath you better and get the pedals out of harms way.

Which is complete bollocks if you are cycling in deep ruts.

I use 165 cranks by preference (shame that Shimano only do Boost in 170 and up) and have them on my Occam. No problem with long rides (e.g. 300km of Cairngorms Loop).

12spd variants of XTR 9100 and 9120 as well as all chainline options on 8100 XT and 7100 SLX come in 165 options.

165mm on road bike and mtb. No issues from a pedaling point of view and does seem to reduce pedal strikes a bit.

Is crank length not dependent on leg length?

I’m a bit over 6ft and have 165s on my MTB. No worries at all and going back to 170 (or maybe 172.5 ?) on teh road bike is no problem

I went from thick flats (Saints) to thinnies (Burgtech Penthouse V) and I didn’t really notice any difference in pedal strikes. It’s the width as much as anything IMHO. Back on SPDs now and very few strikes at all.

So you think 5mm is going to make a difference in a rut, well riding MTB’s for 35 years and being a farmer I know a bit about ruts and riding along them.

Back in the mid eighties I was lucky enough to ride with 4 people from 4 different companies who were designing and building MTB’s they tried all manor of crank lengths 165mm was the least favoured. But at the same time in winter riding some pretty rutted tracks with some bikes with 175mm cranks didn’t seem to slow their progress.

If you are getting a lot of pedal strikes, that is more rider error than cranks that are too long.

I think theres some merit in that. Rider skill does play its part, but there are composite factors. Choosing your equipment to assist has a places, as do geographic location and riding style, plus how low ones BB is.

Mtb has changed rather since the 1980s.
I can’t think of any riders I know that think slogging along ruts is a good thing.

Now, on a rough track with multiple points of variable height, theres a chance that 5mm or even 10mm is going to give some additional clearance for at least some of them.

Especially if you’ve got the gas on and the rear suspension is being worked.

Another Occam owner here and my crankset is 170mm and I have no major issues with pedal strikes

Could you be running a little too much sag on the rear?

I found that I had to add spacers in the DPX 2 as it runs quite plush

Just a thought!

I’ve got a 2020 occam and I’ve had pedal strike issues. Not when climbing as it’s solid when locked out, but loads of scary ones descending at speed. The shock needs massive pressure for my low weight (220 psi for 70kg rider!). I think I’m going to try a bigger volume spacer in the shock to see if it helps. 175mm cranks here too.

I’ve only ever had 175 that I’m aware of anyway.

That said, going to my first 29er (Jeffsy) ive definitely had more issues with pedal strikes but ive mostly just modified my pedaling to compensate.

I find plastic pedals (OneUp) mean that strikes are less harsh. Dunno why. Try running less rear sag as well… the demo bike you tried might have been set up that way.

The weird thing is that going to a new bike with a 5mm lower bb scan feel unrideable, but, in reality, it’s just you. 5mm here or there is nothing, outside of extreme situations.

Just get used to it. After a while you’ll look at the trail and think, “no pedalling there”, and after a bit longer you’ll think, “Ooh, a half stroke here, a quarter stroke there.”

Ladies and gentlemen I give you

The Rut Dodger…..

https://www.instagram.com/p/Bls-v6rBvD3/?igshid=ujkx6jb0u05s

Going from 175 to 165 is beneficial with this type of issue, 10mm reduction does provide a lot more help in reducing pedal strikes over a lot of terrain, especially rocks and roots, the reality is that for some reason the 175mm standard has stuck with us for a long time, not sure why, ebikes seem to be lowering to 155/160 these days due to the issues they have with potentially being lower to the ground more.

Technique can help, but i dare say you’re having strikes going up and level more than down, so the flat and level pedal position isn’t possible all the time, picking lines is good, but again, going over rocks and roots you’ll still have to deal with strikes, get the 165s and give them a try, my enduro has 165s, hardtail has 170, you won’t notice much of a difference to be honest, bar having to lower your saddle by 10mm.

I went to 165mm some time ago largely because I’m short and I felt it eased my knees, but aside from longer lasting effects I couldn’t tell the difference in a blind test.

And for ground clearance 5mm is 5mm. If a light pedal strike could be avoided by lifting the pedal 5mm it’ll achieve it, right?

I have never really suffered with pedal strikes much but my latest hardtail has a very low BB so I do get them in places and have also been looking for thin pedals as a result (well, partly – old ones knackered anyway, wanted SPD with a bit of platform, so shelled out a bit extra for the massive extra 1mm clearance afforded by xtr, will see how I get on). I still think they can easily be avoided with technique, but perhaps we’ve reached a point where it’s necessary for some to adjust setup around pedal strikes, not just technique.

lower your saddle by 10mm

Raise, surely?

I forgot, a mini benefit of my move to 165 a few years ago was to give a fraction more space for a longer dropper post.

The extra 10mm might help you. I’ve ridden with 165 cranks for quite a few of my bikes (think my current one came with 170🤷🏼). If it was my choice I’d spec all my bikes with 165 cranks and average thickness pedals.

There was a blog from one of the Pro Road teams about crank length and I think his take was that it didn’t really make that much difference to them, they just ran what the rider ‘felt’ was best

I run 165 XT cranks and XTR pedals on my spark – after upgrading to 12SP
(I used to have 170s and XT pedals – which are now on my commuter)

This setup change really does help avoid pedal strikes on my local loops.
I have a few climbs where this is important and there is a real difference.

I read something about short cranks being preferred by team sky due to efficiency.
I feel they allow for smoother pedaling.. but how can you really judge.

As regards the XTR pedals being thinner – you can really see it.
XTR Pedals

I’m running 165mm with oneup alloy pedals, definitely getting less pedal strikes and a significant reduction in knee issues.

165mm Cranks and One-up composite pedals here on a large 2020 SantaCruz Hightower. I’m 5ft 10.

The only thing I ‘feel’ is the lack of me twatting my pedals off rocks all the time. No downsides.

It also allows me to run a longer dropper post.

Have subsequently moved my other bike to 165mm too.

I’ve run 175mm cranks on all my bikes for as long as I can remember until I got my Rocket and started getting horrid pedal strikes with it’s 175mm cranks. Switched the chainset to a 165mm one and no longer get pedal strikes but have been whacking the chainring off rocks now instead! Takes about 30 seconds to get used to the different length cranks every time I ride it but after that it’s not an issue. The main difference is the 165’s favour a higher cadence, about 5 rpm more than the 175’s but once I adjust my gear selection accordingly it’s not an issue.

Loads of great input people. Many thanks. Sounds like a plan. I was wondering whether it makes some sections harder as you don’t have the leverage to punt the bike up/over lumps. But presumably that can be overcome by lower gear ratios if needed.

And to the people who say it’s all timing, that may be the case on flats and downhills but I’m talking about uphills and sections where you need to keep pedalling in order not to fall off. There are sections where you can pause, or even do a ratchet half stroke, but there are also loads of places where you can’t. Pausing pedalling means falling off.

And since climbing is where I get 90% of my challenge/ sense of accomplishment biking that’s the bit I focus on.

Having said which, part of the reason for buying this bike is to try this make the downhills fun too.👿

Like I say – sounds to me like you are running too much sag

Put some more pressure in the shock and see how you go

Or try the same sections and make sure the shock is locked out

Like I say – sounds to me like you are running too much sag

Put some more pressure in the shock and see how you go

Soz,forgot to say that I did indeed pump the shock up by 30 psi for the last outing. Might have been better but not good.

Will measure the sag….

What bike are you comparing it to that gets less pedal strikes on the same terrain?

Anthem
Mojo

Hmmm odd.

The mojo 3 has 330mm bb height and 175mm cranks, the occam has 336mm bb height and 175mm cranks.

If everything else is equal the mojo should give you more pedal strikes than the occam.

I’d go for your shock or fork still being too soft, or maybe you run the shock or fork on the mojo mega hard?

I have a mix of 165, 170, 172.5 and 175 across various bikes. I can’t say I notice a difference in feel when swapping between them, as long as saddle height is correct. The 165s were a swap from 175s to help with the same problem you have, there were no downsides. They definitely helped reduce pedal strikes. Technique obviously helps too but there are times you need to pedal such as a tech climb and 10mm may be the difference between clearing or dabbing. Less sag may help too or change the tokens to ride higher in the shock stroke.

There is a lot of past research/opinion that shorter cranks are better as they open up the hip angle so you can spin quicker, breathe better and reduce stress on the knees.

Could anyone tell me whether I need 55 or 52 chainline or something else?

Is this connected with whether the wheels are boost? ( I think they are)https://www.orbea.com/gb-en/bicycles/mountain/occam/cat/occam-m10

There appears to be no stock of 165mm cranks in the obvious places, apart from Holland cycles which has SLX ones with a Q factor of 178 and chainline of 55.

Tweeks reckon they’ll have XT ones in stock in 7 days.

Next stupid question… Is 8100 direct mount by definition?
I can see some weird Allen key bolts on my current ring which suggest they’re not direct mount, but the Orbea website says the gruppo is 8100, so can I take it from that that the current ring will fit the new cranks?

In reply to Julians, the mojo is ancient. A Special Blend from years ago (12 years?)

The shock needs massive pressure for my low weight (220 psi for 70kg rider!). I think I’m going to try a bigger volume spacer in the shock

@Lillski74

Like I say – sounds to me like you are running too much sag

Put some more pressure in the shock and see how you go

Or try the same sections and make sure the shock is locked out

@julians

I’d go for your shock or fork still being too soft, or maybe you run the shock or fork on the mojo mega hard?

Sorry about the delay in replying Julians & lillski. I added yet more pressure to the shock the other day and it did indeed make it betterer. As per the first quote above though, I was flabbergasted by quite how much I had to put in. Running at about 240psi at present.

I’ve not tried them personally but Specialized Boomslang pedals are similarly lean but much cheaper than Stamp 11s and get good reviews.

I also swapped cranks (175>170mm) on my airdrop edit for similar reasons and I haven’t seen any downside. It seems to sit into its travel very readily under power (low anti-squat?) so giving it the beans over rough ground was always sketchy. Several people have asked what difference 10mm makes? Well the answer is if the ground is 170mm away from your BB it makes the difference between whether or not you pedal strike. I definitely noticed an improvement.

@thegeneralist guessing your shock is the x2? Mine is the standard DPS, I’ve fitted a bigger spacer (.6) and I’ll try it on tonight’s ride. An eBay seller 3d prints them so it was cheaper than the crazy fox prices.

So what does a spacer do?
Does it full up volume in the air chamber of something?

So what does a spacer do?
Does it full up volume in the air chamber of something?

yes, it reduces the volume of the air chamber, which in turn makes the shock ramp up more towards the end of its travel. You’d generally use them if you had the sag set correctly, but you were bottoming out the shock far too frequently. Some spacers to reduce the size of the air chamber would make it harder to reach bottom out.

But they also make the shock rebound faster when towards the end of the travel, so they can feel a bit ‘bucky’

I’ve got a 2020 occam and I’ve had pedal strike issues. Not when climbing as it’s solid when locked out, but loads of scary ones descending at speed. The shock needs massive pressure for my low weight (220 psi for 70kg rider!). I think I’m going to try a bigger volume spacer in the shock to see if it helps. 175mm cranks here too.

Hey @davros, do you have a link to the tokens. I’m running between 250 and 270 psi in my Occam just now which seems nuts.

《Oops, soz. Just seen you posted it on the other thread.

Oops.》