Ask the experts

[HankScorpio]

My fat bike is a pig. Easiest way to drop a couple pounds is going tubeless but it came with non-tubeless OEM Maxxis Minions and non-tubeless Sun Rims.

I can seal up the rims with tape and whatnot but can I get the 4.9 inch non-tubeless tires to seal up? I don't want to waste the sealant trying unless I know I can do it.

Anyone have success with this type of tubeless fat bike conversion?

[jm2e]

BB spacer as in the type that goes between the BB cup and the frame? Or as in one that slides onto the crank spindle?

Between BB cup and frame. I suppose you could use the spindle one too. But I’ll bet the frame/cup spacer works better.


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[Cabinfever]

My fat bike is a pig. Easiest way to drop a couple pounds is going tubeless but it came with non-tubeless OEM Maxxis Minions and non-tubeless Sun Rims.

I can seal up the rims with tape and whatnot but can I get the 4.9 inch non-tubeless tires to seal up? I don't want to waste the sealant trying unless I know I can do it.

Anyone have success with this type of tubeless fat bike conversion?

https://m.youtube.com/watch?v=Omj1_-TNovg

This but i used the pink foam that normally goes between a foundation and stud wall to build up the rim bed. Sent you a PM if you want to talk it through.

[jackstraw]

Internally routed shit is really irritating. Bike industry:

Santa Cruz...we made it easy. You're welcome.

[El Chupacabra]

Between BB cup and frame. I suppose you could use the spindle one too. But I’ll bet the frame/cup spacer works better.


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I'll dig around and see what I've got in the parts bin. Thanks.

[XXX-er]

https://m.youtube.com/watch?v=Omj1_-TNovg

This but i used the pink foam that normally goes between a foundation and stud wall to build up the rim bed. Sent you a PM if you want to talk it through.

looks like the old ghetto tubeless setup but with the foam liner is that to give a little more structure to the rim where normaly there is just a rubber membrane ?

I'm interested but I havent even got the new bike yet,

[Dantheman]

The Park Internal Cable Routing Kit is one of my favorite tools on the bench.

I may have to invest. Some companies seem to be doing this a lot better with guide tubes and such, but Commencal just puts a couple holes in the frame and wishes you good luck. Their grommets suck, too. Great bikes otherwise. The Absolut 24 is completely dialed and definitely the best 24" DJ available right now, and it costs a couple hundred less than its competitors.

[Roxtar]

Between BB cup and frame. I suppose you could use the spindle one too. But I’ll bet the frame/cup spacer works better.


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The bb spacers might be too thick for what he's describing. If so, use the spindle spacers.

[joetron]

The bb spacers might be too thick for what he's describing. If so, use the spindle spacers.

Yup. Not a lot of BSA cup spacers out there thinner than 2.5mm.

Also, there’s likely to be a little trial and error involved and spindle spacers will be much quicker and easier to deal with with.


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[joetron]

I may have to invest. Some companies seem to be doing this a lot better with guide tubes and such, but Commencal just puts a couple holes in the frame and wishes you good luck. Their grommets suck, too. Great bikes otherwise. The Absolut 24 is completely dialed and definitely the best 24" DJ available right now, and it costs a couple hundred less than its competitors.

I think it’s worth it. I bought the kit to have at my garage workshop in SLC, but it now lives on top of my bench at the shop.
Basically removes the headache of fishing housing through any frame that doesn’t have TITs (Tubes In Tubes - Does Transition still uses this joke?).


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[jm2e]

Yup. Not a lot of BSA cup spacers out there thinner than 2.5mm.

Also, there’s likely to be a little trial and error involved and spindle spacers will be much quicker and easier to deal with with.


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Well, I'm intrigued now. My money is on a regular old cup spacer fixing the problem. What do you guys think will happen? Right now he tightens it down and there's play. Add 2.5mm, and the play should go away. Am I missing something? Threaded BB cup is literally one of the easiest things to pull on and off a bike.

[joetron]

The fixed length spindle binds the bearings if the crank has less than 2.5 mm worth of play(which is a lot).
Yeah, it’s easy to take cups out, but why remove the cranks and a bb cup when you can just remove the cranks? It probably needs like a .5mm washer on the spindle.


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[Roxtar]

Well, I'm intrigued now. My money is on a regular old cup spacer fixing the problem. What do you guys think will happen? Right now he tightens it down and there's play. Add 2.5mm, and the play should go away. Am I missing something? Threaded BB cup is literally one of the easiest things to pull on and off a bike.

Because 2.5 mm is a lot of space. I'm guessing he doesn't have that big a gap

[El Chupacabra]

This crankset just has a little play - a 2.5mm BB spacer will be too big. Haven't dug around in the parts bin yet, but will look today.

I have a bunch of O rings, and could fit one on the crank spindle as a spacer. Don't know if that would help or hurt though.

[Dee Hubbs]

This crankset just has a little play - a 2.5mm BB spacer will be too big. Haven't dug around in the parts bin yet, but will look today.

I have a bunch of O rings, and could fit one on the crank spindle as a spacer. Don't know if that would help or hurt though.

Visit the Ghost of Christmas Past:
https://www.tetongravity.com/forums/...her-and-spacer

[rideit]

This crankset just has a little play - a 2.5mm BB spacer will be too big. Haven't dug around in the parts bin yet, but will look today.

I have a bunch of O rings, and could fit one on the crank spindle as a spacer. Don't know if that would help or hurt though.

I used a rubber gasket/O ring as a spacer on my XTR for the last two years, it worked perfectly.

[Roxtar]

This crankset just has a little play - a 2.5mm BB spacer will be too big. Haven't dug around in the parts bin yet, but will look today.

I have a bunch of O rings, and could fit one on the crank spindle as a spacer. Don't know if that would help or hurt though.

go to any bike shop. They'll have more little plastic spindle spacers then they know what to do with

[El Chupacabra]

Visit the Ghost of Christmas Past:
https://www.tetongravity.com/forums/...her-and-spacer

Heh. Different bike, different crank, different BB.

But this gave me an idea. Will go check if I have any extra SRAM BBs, in case any came with a thin spacer than didn't get used.

[teleposeur]

Dear experts,
So I'm looking at a new HT, blah blah blah Seat post angles, I understand the desirable nature of steep seat angles for climbing, I've been on an over-forked bike with an unremarkable seat angle for the past several years and its often miserable and sometimes desperate on steep stuff. I have the impression that the push for this is largely coming from enduro, and enduro-bro winch/plummet type of riding for which it makes a lot of sense, and is sexy and sells a lot of bikes, and which comprises much of my own riding! But I'm also a mellow meadow skipping low-angle bro and love me some long xc traversey sort of riding. So I ask is there such a thing as too steep for I guess "trail riding?"
I've not been on many newer bikes, givin' 'er, whats it feel like?

[toast2266]

So I ask is there such a thing as too steep for I guess "trail riding?"

Yes.

The flatter your terrain, and the more time you spend riding on mellow, relatively flat trails, the less you'll (probably) like a super steep seat angle. Steep seat tubes work as advertised on steep climbs, but on flatter stuff they can make the cockpit feel cramped, they put a lot of weight on your wrists, and the bike handling can feel a little weird on seated, flat riding.

And just to complicate things, pay attention to the actual angle vs. effective angle. The longer your legs, the more the actual angle matters.

As with anything, it's a trade off, and there is surely a perfect middle ground for you and your trails. No idea what that middle ground is for you though.

[SchralphMacchio]

But I'm also a mellow meadow skipping low-angle bro and love me some long xc traversey sort of riding. So I ask is there such a thing as too steep for I guess "trail riding?"
I've not been on many newer bikes, givin' 'er, whats it feel like?

When you say new HT, do you mean Hightower or hardtail?

I agree with toast 100%. Example, my hardtail has such a steep seat post angle (actual, not effective, thanks to an aggressively bent seat tube, Guerilla Gravity Pedalhead) that it’s the first bike where I’ve put the saddle clamp at the front of the rails whereas on my other bikes it’s usually been opposite.

One brand I’ve noticed that hasn’t gotten *too* steep with seat tube angles is Pivot. I think both on the Switchblade (in case Ht means Hightower) and Trail 429 the angles aren’t super progressive and make a pretty well balanced bike overall. They’ve opted for stiff frame design without super aggressive geo - it’s worth a demo if feeling balanced is at least as important to you as having fun on the rowdy bits.

[El Chupacabra]

No luck on eliminating the play in the crankset. Tried a tiny thin spacer on the NDS crank, and as soon as I started tightening it down, the bearing over- preloaded and cranks became difficult to turn.

I think the BB must be wearing out, slowly. With cranks removed, the bearings spin smooth by hand and I don't feel any play. Install cranks and torque to spec, and I can feel a little play at the end of the crank, both sides.

We have 3 other bikes in the house with GXP cranks, and none have play, not even the old SS that has a notchy BB bearing on one side.

[Roxtar]

No luck on eliminating the play in the crankset. Tried a tiny thin spacer on the NDS crank, and as soon as I started tightening it down, the bearing over- preloaded and cranks became difficult to turn.

I think the BB must be wearing out, slowly. With cranks removed, the bearings spin smooth by hand and I don't feel any play. Install cranks and torque to spec, and I can feel a little play at the end of the crank, both sides.

We have 3 other bikes in the house with GXP cranks, and none have play, not even the old SS that has a notchy BB bearing on one side.

one other thing to check. GXP crank spindles are cut down on one side. Make sure the bottom bracket bearing on that side is the correct ID to match

[Roxtar]

I believe it's 24mm on one side and 22mm on the other. The small side bottom bracket bearing should have a plastic insert on the ID

[El Chupacabra]

It's installed correctly. The BB and crankset are the stock ones that came on the bike - GXP Descendant carbon crank, not sure which model BB, but the dust caps say SRAM. Bike is a Diamondback Release 5C, drivetrain is mostly XO1 Eagle.

There wasn't play earlier in the life of this bike - I only noticed the play in the crank because I was looking for the source of a suspension clunk. (A pivot axle had loosened, so I removed, cleaned, regreased, and reinstalled all the pivots.)