Ask the experts

[jackstraw]

Hilarious.

25 years ago: "I honestly can't believe I used to ride shit strapped all over my bike. Now when I ride I will have everything on my back in a hydration pack and it's amazing."

Full circle. Dayglow and hair bands coming next

[dfinn]

I ignored a creak that I thought was new pedals, it was mildly annoying for a while. I meant to look at it but kept forgetting to. Went on a really long solstice ride. It got really bad, I was just trying not to bonk but took a quick break to tighten everything up and couldn't find anything loose. The next day I was looking over the bike and I realized it was my drive side crank that was really, really loose. I tightened it up but it quickly came loose again on yesterdays ride. They are SRAM XO Dub cranks. Am I looking at new cranks?

[Dee Hubbs]

I ignored a creak that I thought was new pedals, it was mildly annoying for a while. I meant to look at it but kept forgetting to. Went on a really long solstice ride. It got really bad, I was just trying not to bonk but took a quick break to tighten everything up and couldn't find anything loose. The next day I was looking over the bike and I realized it was my drive side crank that was really, really loose. I tightened it up but it quickly came loose again on yesterdays ride. They are SRAM XO Dub cranks. Am I looking at new cranks?

Most of the problems are people not being able to loosens he bolt on DUB cranks.
Do you have the correct spacer(s) on the DUB bottom bracket?
The torque setting for the driveside 8mm hex bolt is really high. Like 50+ N.m. After tightening you need to hammer the crank fully towards the non-driveside and then adjust the preload adjuster.

[dfinn]

I will give that a try. These had been on the bike and been fine for quite a while.

[El Chupacabra]

What's the advantage (theoretical or real) of the DUB or Race Face cinch type crank vs GXP or Shimano 24mm type? The preload adjustment seems fiddly.

[dfinn]

I think my preload ring may be broken. I spun and spun it towards the “+” symbol and nothing happened.

Followed this vid:

https://youtu.be/8euYre5FNes

[simple]

What's the advantage (theoretical or real) of the DUB or Race Face cinch type crank vs GXP or Shimano 24mm type? The preload adjustment seems fiddly.

Dub got a aluminum spindle vs the GXP steel. So about a quarter pound of weight savings.

[Dee Hubbs]

I think my preload ring may be broken. I spun and spun it towards the “+” symbol and nothing happened.
Followed this vid:
https://youtu.be/8euYre5FNes

Pull the preload rings off the crank and see if they still thread together and expand as they are suppose too. If they are fawked they are only a $5 item from your local shop.

[Terrapin Ben]

Pull the preload rings off the crank and see if they still thread together and expand as they are suppose too. If they are fawked they are only a $5 item from your local shop.

Do yourself a favor and buy the $30 cane creek aluminum preloader.

[HankScorpio]

Do yourself a favor and buy the $30 cane creek aluminum preloader.

Yes, worth every penny getting this. I’ve had great luck with the CC preload ring and Race Face cranks. Very solid and easy to set up.


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[Roxtar]

What's the advantage (theoretical or real) of the DUB or Race Face cinch type crank vs GXP or Shimano 24mm type? The preload adjustment seems fiddly.

The new Shimano XTR cranks have gone to the same RF style preload. I've never had an issue with the RF Cinch. Nice, simple, and reliable.

[dfinn]

Do yourself a favor and buy the $30 cane creek aluminum preloader.

Thanks! I'll pick one of those up.

[toast2266]

What's the advantage (theoretical or real) of the DUB or Race Face cinch type crank vs GXP or Shimano 24mm type? The preload adjustment seems fiddly.

GXP just had the wavy washer for bearing preload, which wasn't great.

The shimanos at least had the bearing preload via the non drive crank clamp, which worked well.

But yeah, 30mm spindle is lighter. And at least some of them (e.g. cinch) are replaceable. Which is nice if you're swapping cranks to a frame with a different bb width - just swap the spindle.

Main downside is smaller bearings in the bb.

[mall walker]

any gotchas to look out for when adjusting the internal travel of an air suspension fork? (letting out air, removing the lower bit, adjusting it, etc)

[dfinn]

any gotchas to look out for when adjusting the internal travel of an air suspension fork? (letting out air, removing the lower bit, adjusting it, etc)

make sure ALL the air is out of the air spring side. Nearly lost an eye last year because there was a little bit left in there but man that thing was a rocket. Grazed my cheek and shot across the garage.

[toast2266]

make sure ALL the air is out of the air spring side. Nearly lost an eye last year because there was a little bit left in there but man that thing was a rocket. Grazed my cheek and shot across the garage.

If you want to be sure, just pull the valve core out.

[mall walker]

getting lazy about fully draining the air definitely sounds like something I would do. good to know lol.

[SchralphMacchio]

make sure ALL the air is out of the air spring side. Nearly lost an eye last year because there was a little bit left in there but man that thing was a rocket. Grazed my cheek and shot across the garage.

Which can mean equalize on the way down too! If you depress the valve you’ll empty the + air chamber but there will still be pressure in the -; equalize on the way down and you’ll see pressure rebuild back in the +.

[Rossymcg]

Which foot forward through turns? I am trying to improve and have always ridden with the dominant foot forward. The other crank arm & pedal has a lot of damage from rock strikes. Should I have my inside foot forward through the turn since the rear wheel tracks on a tighter line.

It feels weird when taking drops & turns with the other foot forward and hard to get use to. Really hard to drop the heel.

get someone to push you from behind, which ever foot goes forward to save you from falling is your front foot. ouside foot pedal down any type turn you wont ever be wrong. Im usually always outside foot down it lets me lean my bike more under me

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[Dee Hubbs]

But yeah, 30mm spindle is lighter. And at least some of them (e.g. cinch) are replaceable. Which is nice if you're swapping cranks to a frame with a different bb width - just swap the spindle.

Main downside is smaller bearings in the bb.

I agree that the 30mm axle is lighter. The greater the diameter of the axle, the thinner (lighter) the material can be to create that axle.
As for bearing size, there is room for equal size bearings in a 30mm system vs a BSA system.
BSA is 1.37 inches or 34.8mm opening for a 24mm axle. But the bearings are external of the frame to utilize full size bearings.
PF30 has a 46mm opening for a 30mm axle. So a 16mm allowance for bearings and housing.
BB30 has a 42mm opening for a 30mm axe. So a 12mm allowance for bearings and no housing required.

Unless you're referring to BSA to 30mm, and even then the bearings are located external to the frame and can still use full size bearings.

OR maybe you're referring to BB86/BB92 (or referred to as PF41 by Hope (as in the frame opening) or referred to as PF24 by Chris King (as in the axle diameter). THEN yes, as this type of BB has a frame opening of 41mm and an axle axle of 30mm and only 11mm inside the BB for bearings and housing. This system has very small/thin bearings and is prone to premature bearing wear/failure.

This is why SRAM went to the DUB 28.99mm axle. It allows them to use a full size bearing inside a 41mm frame opening. It allows them to produce a DUB BB for almost any frame configuration.

I haven't even touched on axle length vs BB shell width. Fawk I hate BB "standards"

[El Chupacabra]

In real life, does that extra 1mm allowed by SRAM's DUB (28. 99) vs Race Face (30) - - when used in a PF41/ BB92 press fit bottom bracket shell - - provide for significantly better bearing life?

[HAB]

In real life, does that extra 1mm allowed by SRAM's DUB (28. 99) vs Race Face (30) - - when used in a PF41/ BB92 press fit bottom bracket shell - - provide for significantly better bearing life?

Not sure about the press fit BBs, but the BSA Dub BB uses a plastic spacer between the bearing and the spindle. The ID of the actual bearing is still 30mm. The Cinch BSA doesn't have a spacer there, the bearings ride on the spindle directly. IIRC it also uses a bigger OD bearing than the Dub ones.

[jackstraw]

I have to buy a threaded 73mm BB and Crank for 2016 Hightower. I'm more confused than ever reading this thread.

[Dee Hubbs]

In real life, does that extra 1mm allowed by SRAM's DUB (28. 99) vs Race Face (30) - - when used in a PF41/ BB92 press fit bottom bracket shell - - provide for significantly better bearing life?

Yes, It allows them to use an industry standard (I mean industrial bearing standard, not a fawking bike standard) off the shelf bearing manufactured to high standards and tolerances based off of the load vs bearing size to increase wear and life.
Where as the RaceFace 30mm axle crammed into a 41mm hole has to use a specially spec'd and limited run production bearing that uses undersized balls for the load that it is expected to carry.
When the 30mm axle was designed, the engineers/product managers never imagined that people would try to jam a 30mm axle into a 41mm bottom bracket shell, and it wasn't until Race Face (who bough Easton (who had the carbon fiber crank technology) who was then bough by Fox) decided to go to 30mm axles across their whole line (to reduce SKU's). They engineered and made the 30mm to 41mm BB readily available, and solved the BB shell width issue by making the cinch system connection on both arms allowing for swiping out different axle lengths.

[buttahflake]

Damn, you motherfuckers know your shit. Very informative thread.