Right, a guy has mis-sold some cranks as 170mm when they were 165mm. I think he is happy to take them back but….

Should I give them a try (i dont mean try then send back, i mean try/keep). I usually run 170mm on my downhill bike. I have googled and lots of people seem to use 165mm on DH bikes. Would it be such a bad thing? I’m 5′ 10, although I am not sure this matter so much with DH.

So I think my question is, are you 5′ 10 or over and running 165’s on a DH bike?

165mm is the default for DH. If you’re putting them on the DH bike then keep them.

Height doesn’t really come into it really, as DH bikes have really low BBs you want really short cranks so you don’t bash them as much.

I went from 175s to 165s on my enduro. No problem. Much prefer it. I’m 5’10”.

This (Pauls post) ^

🙂 ok cool… that sounds like it saves me a load of hassle… appreciate the replies…

yes it is for a DH bike…

i’m 6’2″ and went from 175 to 165 on my enduro bike, much prefer it. keep them if the length is your only worry, you’ll rejoice at the extra pedal/ground clearance!

I thought it felt a wee bit weird- not pedalling or anything, but I could feel the difference in stance when not pedalling. Didn’t think I would, I can’t tell any difference between 175 and 170. But, it wasn’t a bad thing, just different, and bonus ground clearance…

Friend went from 175 to 165 on his bike and no one’s seen him since. Makes you think, could happen to you.

Can someone explain why there’s a desire for super low BB’s, and short cranks? Surely short cranks are raising your COG by almost half an inch, which is enough if you believe the internet to ruin a #ENDURO bikes geometry? Why not ride a bike with 1/2″ higher BB and 175mm cranks?

Yeah, unless you run them 180 degrees apart like most people do

Surely short cranks are raising your COG by almost half an inch,

I don’t get it. Surely your weight is on the bb axle no matter where your feet are.

Chrishc777 spot on.

Can someone explain why there’s a desire for super low BB’s, and short cranks

Stability without so many pedal strikes.

I don’t get it. Surely your weight is on the bb axle no matter where your feet are.

No, the weight is wherever you’re loading the bike – I’ve noticed I can balance a drift much better with my outside pedal dropped than with pedals level. Like how when you’re undoing a nut the torque relates to where you’re gripping the spanner, and the dropped crank is a longer lever around the bike’s centre of lean.

There’s a complex 3D forces diagram that needs drawing, taking into account contact patch shape and location, head angle and fork offset, BB height, axle height, crank length, pedal width etc.

Stability without so many pedal strikes.

Yep. My new hardtail’s bottom bracket is 40mm lower than my old one. Super stable and I don’t usually have to think about pedalling to avoid strikes because that habit already fairly well programmed. I’m not sure how well I’d have got on with it as a beginner though!

Jokes aside cgg is right, however 10mm in that instance is possibly negligible

Always used to use 165 cranks on my old dh bike, more clearance, as said above.

Cheers again… I am definitely going to give the 165’s a burn…

I would for a DH bike.

However please post back before too long so we know you’re still alive!

Don’t see why anyone would ever need anything longer really – why are 175mm the standard length?

chrishc777 – Member

Jokes aside cgg is right, however 10mm in that instance is possibly negligible

Your COG is decided by your body position, not your cranks- if your pedal is at 6 o’clock and your leg and body is straight then yes your COG is higher but you’re also about to crash so you have bigger problems.

Probably a roadie thing, I can see the advantange of extra leverage on the road where there’s no disadvantage.

Just like front mechs I suppose..

*runs for cover

EDIT: Northwind yes you’re right on the COG thing, I think the wording wasn’t perfect but the lower you can drive your weight on the outside pedal the more grip you can get from the tyres, or something like that

Your COG is decided by your body position, not your cranks- if your pedal is at 6 o’clock and your leg and body is straight then yes your COG is higher but you’re also about to crash so you have bigger problems.

It isn’t about COG, it’s about how the force from gravity acting on your mass applies itself to the bike. There’s something bloody complicated going on, related to levers and fulcrums and contact patches but the important thing from my perspective is I know I can drift a bike better with a lower BB but if I load it through a dropped pedal rather than level pedals, it’s even more stable.

I’m going to go out on a limb and say when TINAS specifically said “centre of gravity”, it was about centre of gravity.

I’m going to go out on a limb and say when TINAS specifically said “centre of gravity”, it was about centre of gravity.

You’re right, he did and it was! But he missed that point as did I this…

Anyway, cranks only vary in length by 15mm max. Bottom bracket heights vary by about 50mm.

Wording wasn’t perfect Northwind but we all got what he meant, c’mon, it’s Friday

One of my mates put 165mm cranks on his trail bike and then his wife fell pregnant.
Just sayin’.

Oh and yes keep them.