Alternative to Sram Dub bottom bracket?

trob6 · Post by **trob6** » Sat May 02, 2020 8:45 am

I have a Sonder broken road which I got last year and the first bottom bracket lasted 962 miles before the drive side seized solid, Alpkit replaced it under warranty but now this one is started rumbling and its not done anywhere near the miles the last one did.
My friend has a new Santa Cruz and his Dub bb seized after a couple of months also,.
I thought about just replacing the bearings so took one out last night, its a 6806 which comes as 42mm OD but the bearing I took out measures 40mm od so I think sram either machine them down or have there own made either way I am looking for recommendations for a replacement, Hope is up there but with the converter cups its over £100, I have hope bbs on my other 2 bikes and I know they are good just seems a bit pricey.
I don't pressure wash and I did service the first bb after 500 miles and it was spotless internally then, there was no creaking it worked one day and was seized the next.
All suggestions greatly received.
Tim.

sean_iow · Post by **sean_iow** » Sat May 02, 2020 9:08 am

I'd would say Hope but I think the Dub conversion only works with the 30mm bb and that also needs a different tool to fit so that might also be an extra cost if it's different to the Sram dub tool.

Does the dub bb have a central tube? The Hope 30mm one doesn't and I'd worry that might mean any water that gets in could get into the bearings as there's only one seal to stop it.

All of this assumes the broken road has a threaded bb.

whitestone · Post by **whitestone** » Sat May 02, 2020 9:36 am

I don't think any spindle of greater than 24mm diameter has a protective tube on threaded BBs (from Alpkit's site it looks like the Broken Road has a 73mm threaded shell) - there isn't room for it in the BB shell.

From memory Santa Cruz were one of the few manufacturers to refuse to use press-fit BBs so likely to be a threaded BB.

Many will have seen Hambini's video rants, I listened to an interview with him. Turns out he's a Hope fan boy but he reckons their 30mm BB isn't up to much and they only produced it to cover the market. His comments about SRAM Dub are NSFW!

Doesn't help the OP, sorry.

BigdummySteve · Post by **BigdummySteve** » Sat May 02, 2020 10:04 am

I think you might have difficulty finding the bearings separately, SRAM DUB has a 29mm spindle which is not a commonly available size.

BigdummySteve · Post by **BigdummySteve** » Sat May 02, 2020 10:07 am

This might help, £15 conversion kit from Hope, looks like a shim to enable the use of 30mm bottom brackets.

https://www.18bikes.co.uk/hope-dub-bott ... rsion.html

Mike · Post by **Mike** » Sat May 02, 2020 10:18 am

watching closely as i have a dub bb and at some point will need to change or replace

BigdummySteve · Post by **BigdummySteve** » Sat May 02, 2020 10:26 am

BigdummySteve wrote: ↑Sat May 02, 2020 10:04 am I think you might have difficulty finding the bearings separately, SRAM DUB has a 29mm spindle which is not a commonly available size.

Proven myself wrong

https://www.kineticbikebearings.com/6806-29-llb.html

The key is 6806/29 indicating a 29mm bearing bore

trob6 · Post by **trob6** » Sat May 02, 2020 10:45 am

The Broken Road does have a threaded bb and the dub kit does have a central tube and I have the 30mm threaded hope one on my hardtail so I'm aware it has no tube.
I'm going to email Neil at Alpkit and ask if he knows of anything that may be any good, my other option is to buy a new set of 30mm cranks and then that opens up a whole load of options, I think sram was trying to fix an unbroken thing and proceeded to break it.

trob6 · Post by **trob6** » Sat May 02, 2020 10:49 am

BigdummySteve wrote: ↑Sat May 02, 2020 10:07 am This might help, £15 conversion kit from Hope, looks like a shim to enable the use of 30mm bottom brackets.

https://www.18bikes.co.uk/hope-dub-bott ... rsion.html

Thanks, I have seen these, that's how it get over £100 with the bearings as well.
The dub internal size is 30mm and has a small plastic tophat shaped shim that sleeves it to 29ish so my worry is the shim (hope or otherwise) is so thin that it wont last long hence the new cranks option?

Cheeky Monkey · Post by **Cheeky Monkey** » Sat May 02, 2020 10:54 am

First, what's dub? Second, is the BB faced and everything aligned and true?

trob6 · Post by **trob6** » Sat May 02, 2020 11:18 am

Cheeky Monkey wrote: ↑Sat May 02, 2020 10:54 am First, what's dub? Second, is the BB faced and everything aligned and true?

Dub is the new crank size that sram have invented it 28.99mm or something like that, I just spoke to my local bike shop and they asked the same thing and said to take in in when I get a new bb and they will face it off for me but I would like to think that it is ok.

ton · Post by **ton** » Sat May 02, 2020 11:43 am

my ecr came with some shyte sram nx crankset and corresponding bb. it has died after about 500 miles. absolute shyte stuff.

i have a old xt crankset and a absolute black 30 tooth ring to go on it, fitted with a nice bb52.

BigdummySteve · Post by **BigdummySteve** » Sat May 02, 2020 12:15 pm

Are the DUB bearings I linked to not the easiest and cheapest solution? Knock the knackered bearings out and replace, 10min job.

trob6 · Post by **trob6** » Sat May 02, 2020 2:55 pm

BigdummySteve wrote: ↑Sat May 02, 2020 12:15 pm Are the DUB bearings I linked to not the easiest and cheapest solution? Knock the knackered bearings out and replace, 10min job.

I have just knocked the bearing out of my friends knackered dub bb ( he left it at my garage when we changed it before lockdown ) and the bearing is a 6806 but measures 40 x 30 x 6 with vernier calipers and the link above says 42 x 29 x 7 ?

BigdummySteve · Post by **BigdummySteve** » Sat May 02, 2020 3:02 pm

Hmmm, is actually a dub crank, I thought they had 29mm spindles and 42mn bearings, the SRAM bullshit was that extra 1mm gave space for improved bearing seals, if they have reduced the bearing to 40od and 30id then the balls will be of mouse proportions, no wonder they don’t last. I’d go for the hope plus adapter solution. They last reasonably well and dead easy and cheap to change bearings.

boxelder · Post by **boxelder** » Sat May 02, 2020 3:53 pm

I bought the Nukeproof one https://www.chainreactioncycles.com/nuk ... prod187151 as the BB on my Spearfish was a bit hesitant after being sat for a while. It's much better quality than the stock on - feels similar to Hope. The original eased up though and seems OK, so no test feedback yet.

sean_iow · Post by **sean_iow** » Sat May 02, 2020 4:30 pm

If the bearing is marked 6806 that's a 42x30x7. Without wanting to sound patronising could you have mis-measured it? Or misread the code on it? Bearings always conform to the dimensions of the code (in my experience) as that's the point of putting the code on.

Back to the original problem, are there different spec dub bb's? If so have you thought about getting one further up the range?

trob6 · Post by **trob6** » Sat May 02, 2020 5:56 pm

sean_iow wrote: ↑Sat May 02, 2020 4:30 pm If the bearing is marked 6806 that's a 42x30x7. Without wanting to sound patronising could you have mis-measured it? Or misread the code on it? Bearings always conform to the dimensions of the code (in my experience) as that's the point of putting the code on.

Back to the original problem, are there different spec dub bb's? If so have you thought about getting one further up the range?

I thought the same Sean I must have measured it wrong! Bearing is marked cw-sram 6806-W6LHV and I have checked my calipers against known dimensions in case they are wrong and checked the bearing and cups several times it case I'm being a clot but it still measures the same.
The bearing must have been machined down to make it nice and weak?
No different spec they are all the same, I am coming to the conclusion that My Hope will be getting some cash from me shortly.

sean_iow · Post by **sean_iow** » Sat May 02, 2020 6:04 pm

Tim, this is an interesting read

https://wheelsmfg.com/blog/what-is-sram-dub.html

They state the bearing is a 6806/29 and it's 42x29x7

Wheels manufacturing might be another option?

trob6 · Post by **trob6** » Sat May 02, 2020 6:29 pm

I'm going to pop down to my work shortly and pick up my other set of calipers and check again, I shall report back.

trob6 · Post by **trob6** » Sat May 02, 2020 6:35 pm

https://nsmb.com/articles/why-so-angry-about-sram-dub/
Scroll down a bit and they ask Roberts Graudins about bearing size to which he replies it isnt an off the shelf bearing!
Hurrah I'm not going mad

trob6 · Post by **trob6** » Sat May 02, 2020 7:19 pm

Checked the bearing and cup with another set of calipers and its still the size i said.

Alternative to Sram Dub bottom bracket?

Alternative to Sram Dub bottom bracket?

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