Ask the experts

[Tailwind]

A friend has one of these and likes it. I built it for her. Build quality of spots is “pretty good”. Not on part with a high end mountain bike (pivot or Santa Cruz for example) but maybe in line with what I’ve seen from Revel. She runs a rear rack and it’s a clean setup.

Utility is great. The price is well worth it if you use the dynamo hub which is pretty sweet… I’m jealous of the simplicity as I constantly plug in my lights to charge.

Anyone have thoughts on the Spot Acme, currently being for $1400 vs the regular $2200
https://spotbikes.com/products/acme-...31914008150050

I need a new townie bike and I've always wanted to run a belt drive. Have considered the Priority Hot Sauce which has a cool vibe, but you're paying $950 for a lot of bargain bin components...and I'm not sure I can deal with the Medium/Large size at 6'2" and still have enough space for mounting things like a kid seat or front rack.

The Acme seems like a pretty sweet bike for the price. Cons seem to be that it can't clear much bigger tires and it has limited front-rack mounting options (need to use something that can mount to the axle since it is a carbon fork and has no rack eyelets).

I don't think I could build something for less (even if I were gonna attempt a DIY belt drive conversion with a braze-on belt drive coupler)

[North]

Anybody have an opinion on SRAM Dub (pressfit ) bottom brackets? Mine just died. Bike is on its 3rd season, so it's not the fastest I've ever cooked a BB, but it is the worst I've seen on one of my bikes (non drive side almost completely locked up).

[jdadour]

Anybody have an opinion on SRAM Dub (pressfit ) bottom brackets? Mine just died. Bike is on its 3rd season, so it's not the fastest I've ever cooked a BB, but it is the worst I've seen on one of my bikes (non drive side almost completely locked up).

I recently needed to install my first ever press fit bottom bracket on my Cervelo Aspero. Opted to get a Wheels MFG which also threads together on the inner sleeve. More pricey but seems worth getting something that is better engineered and will last longer.

https://wheelsmfg.com/bottom-brackets.html

[Roxtar]

I recently needed to install my first ever press fit bottom bracket on my Cervelo Aspero. Opted to get a Wheels MFG which also threads together on the inner sleeve. More pricey but seems worth getting something that is better engineered and will last longer.

https://wheelsmfg.com/bottom-brackets.html

Essential part for pressfit. Enduro also makes one.

[Eluder]

Anybody have an opinion on SRAM Dub (pressfit ) bottom brackets? Mine just died. Bike is on its 3rd season, so it's not the fastest I've ever cooked a BB, but it is the worst I've seen on one of my bikes (non drive side almost completely locked up).

It's not cheap, but this is the best PF BB I have ever used. https://www.bbinfinite.com/pages/mountain

[Falcon3]

What’s the part number for the rebound knob on a Zeb? I lost the set screw and it’s proprietary and doesn’t come by itself I guess

2022 Zeb Ultimate - Charger 2.1

[Falcon3]

What’s the part number for the rebound knob on a Zeb? I lost the set screw and it’s proprietary and doesn’t come by itself I guess

2022 Zeb Ultimate - Charger 2.1

[jamal]

Should be in the sram spare parts catalog somewhere.


For bbs I have a couple of the thread together wheels mfg ones. I'm not completely sold on them for a couple reasons- one being that the bearings are in a different spot vs the sram ones so you have to trial and error the spacers and try to get the right left-right difference so the chainline is right. where sram just has a chart. So like with my new gravel/cx bike I go into the sram chart and see that they call for a 3mm spacer on the ds and nothing on the right and then i wind up with like 5.5 and 2.5 or something and oh wait the preload thing is way way out so lets put another 0.5mm in there somewhere. Then also you have metal on metal and that does wear the crank spindle over time where the sram bbs have plastic sleeves in there.

My trek hardtail has a standard sram dub bb in it and is still fine after two seasons. My fancy wheels mfg bb in the orbea gravel bike is on it's 3rd set of bearings this year. I bought a regular sram bb to try next time they wear out (which will be soon, with cx starting in a few weeks). The bearings are at least cheap and easy to change especially if you have a nice wind out bearing extractor. Getting the whole thing in the frame and torqued to spec is tricky though. You want the wheels press kit and the bb socket that threads onto it so you can use the press tool to hold the socket on the bb splines.

The wheels thread together bb in my pf30 cannondale road bike has been good and quiet though. And their real expensive PF41 dub double row bearings in the hei hei seem to hold up pretty well too.

I'm not sold on the bbinfinite etc bbs that press in from one side because they can and do back out.

[toast2266]

I'm still in the "buy whatever bottom bracket is on sale for ~$50 and replace it when it gets shitty" camp.

Sometimes you'll replace a couple in a year. Sometimes you'll get a couple years out of one. Either way, it's still cheaper than buying a fancy one that may or may not actually last longer. They're not *that* hard to replace, and when they go bad, it's not like they're gonna leave you stranded in the backcountry. They just get annoyingly creaky or the bearings get rough.

Sent from my SM-S901U using Tapatalk

[Tailwind]

Is there any reason chainline would get worse on a bike with a smaller front chainring?

Canyon Grizl. 1x11 Shimano. Leaving on a 10 day bikepacking trip Saturday.

I had a 44 tooth front chainring on there and it shifted fine. I went to a 40 tooth and it started hopping in the 11 tooth cog. It’s when I pedal moderately hard, it starts popping. It doesn’t happen in the stand. I assumed it must be the b gap but I adjusted that with no success. I just installed a 36 tooth front chainring and it seems to be even worse…

Things I’ve checked / done:
* hanger is straight
* shortened the chain.
* limits are correct
* cable tension is correct
* removed and cleaned cassette - torqued properly.

Zero change or improvement.

What I’ve noticed : when pedaling backward in the stand the chain ‘hops’ up the cassette a little every once in a while. Looking at it, the chain has to cover a lot of ground across the cassette and I’m wondering if it’s possible that the smaller ring means it’s catching on the ramps for the next shift up.

It’s quite possible my 11 tooth on the cassette is fubared but that feels odd.

Might try to find another rear wheel or panic buy a new cassette but open to ideas.

[Eluder]

What’s the part number for the rebound knob on a Zeb? I lost the set screw and it’s proprietary and doesn’t come by itself I guess

2022 Zeb Ultimate - Charger 2.1

I'm pretty sure all the mid to upper RS forks use the same knob. Let me double-check that, but if so, I can send you a used one from a blown damper.

[D(C)]

I got one of these and it’s still running great 3 years later: https://wheelsmfg.com/bottom-bracket...m-bracket.html

Do you know why you’re going through bbs? The main culprits in the past for me have been water sitting in the bb shell, or out of tolerance bb shell that causes the bearing to bind.

[frorider]

Following up on my UDH discussion in the Idiot thread—turns out there is a machined 7075 alu option from Burgtec if you’re looking for something strong.

Wheels Mfg uses machined 6061, which I’m sure is far better than the cheesy cast $15 ones out there.

[Dee Hubbs]

Following up on my UDH discussion in the Idiot thread—turns out there is a machined 7075 alu option from Burgtec if you’re looking for something strong.

Wheels Mfg uses machined 6061, which I’m sure is far better than the cheesy cast $15 ones out there.

Also North Shore Billet makes a 6061 version without plastic ring, all metal. Pricey at $53 USD, but better than the cheesy ones.

[jamal]

First set of bearings i trashed after a 3 day gravel race in the rain/mud. Thankfully my headset was ok because the fucking brake hoses go through it. 2nd set I was getting a click and noticed one bearing was a little crunchy so I replaced them both, and now have a spare sram bb for it. What actually solved click was removing pedals and cleaning and re-greasing the threads.

Might try to find another rear wheel or panic buy a new cassette but open to ideas.

Is the H limit too close in? Upper guide pulley should be lined up with the outside edge of the 11t, not aligned. If it's too close you'll get the chain trying to ride up on the next cog. Otherwise yeah I'd say your cassette is just worn out, especially if this is a new chain.

[frorider]

Ya I didn’t mention NSB in this particular thread. Pretty much none of the >$20 hangers use plastic ring. With the burgtec using stronger, harder to machine 7075 yet around $40 (like WM) it seems the best choice.

[Roxtar]

I'm still in the "buy whatever bottom bracket is on sale for ~$50 and replace it when it gets shitty" camp.

Sometimes you'll replace a couple in a year. Sometimes you'll get a couple years out of one. Either way, it's still cheaper than buying a fancy one that may or may not actually last longer. They're not *that* hard to replace, and when they go bad, it's not like they're gonna leave you stranded in the backcountry. They just get annoyingly creaky or the bearings get rough.

Sent from my SM-S901U using Tapatalk

I wouldn't recommend that route for press-fit, though.
The problem with press-fit BBs, especially with carbon frames, isn't the bearings going out. It's that every time you replace one, that frame ID opens up slightly (the material stretches), and you have a slightly weaker press. That's the creaking inherent in PF BBs. It gets worse with each replacement.
I'd really recommend spending the coin for a BB that won't need replacing in this application.

[sfotex]

Following up on my UDH discussion in the Idiot thread—turns out there is a machined 7075 alu option from Burgtec if you’re looking for something strong.

Wheels Mfg uses machined 6061, which I’m sure is far better than the cheesy cast $15 ones out there.

I don't want a pot metal derailleur. hanger, but something needs to give in the system if you give it a good whack and a hanger is cheaper then the frame or the rear derailleur.

[skaredshtles]

<snip>
I'd really recommend spending the coin for a BB that won't need replacing in this application.

Recommendations?

[Roxtar]

Following up on my UDH discussion in the Idiot thread—turns out there is a machined 7075 alu option from Burgtec if you’re looking for something strong.

And they're dead-sexy looking

[Roxtar]

Recommendations?

Enduro & Kogel both make some really nice BBs. The Enduro XD-15 is right up there with CK (price-wise also)
My favorites for creak-free-press-fit is the thread-together models from Enduro (Torqtite) or Wheels Mfg. Both turn press-fit into threaded.

[toast2266]

I wouldn't recommend that route for press-fit, though.
The problem with press-fit BBs, especially with carbon frames, isn't the bearings going out. It's that every time you replace one, that frame ID opens up slightly (the material stretches), and you have a slightly weaker press. That's the creaking inherent in PF BBs. It gets worse with each replacement.
I'd really recommend spending the coin for a BB that won't need replacing in this application.

I think you're replacing bottom brackets a lot more than I am.

Most bikes I'm keeping for 3 or maybe 4 years tops. I'll maybe swap the BB 2-3 times in the time I own the frame. Even in a carbon frame with a pressfit BB, that's totally fine.

[Tailwind]

Is the H limit too close in? Upper guide pulley should be lined up with the outside edge of the 11t, not aligned. If it's too close you'll get the chain trying to ride up on the next cog. Otherwise yeah I'd say your cassette is just worn out, especially if this is a new chain.

Thanks! My neighbor has a mountain bike with an 11-46 Shimano cassette. I borrowed the smallest two cogs off that this morning and it immediately fixed the issue.

The chain is pretty new but has 300 or so miles on it. Working theory is that I noticed it more with the smaller chainrings because suddenly I was using the 11 tooth cog more and maybe I just pushed it past the brink in the last bit of riding.

[Eluder]

Once I stopped cleaning my bike all the bearings amazingly last longer.

[skaredshtles]

Once I stopped cleaning bike all the bearings amazingly last longer.

Shhh... don't let out the secret.