Bassi Hog's Back

It’s definitely an x type spider?

Sorry for being late to the party, but Cotic have them for £99/pr

https://www.cotic.co.uk/item/outlet_brakes_deore_m6100_set

Yup, though looks like I may need to space out the 68mm BB? I now realise the photos taken last night didn’t have the lockring flush with the BB (despite the DS crank bolt being tightened all the way).

This morning, I moved the DS assembly in by force of hand to take up the slack (the lock ring is now flush with the BB) but that’s meant the NDS assembly is now jutting right out and the lockring, even when wound all the way inwards, runs out of threads.

In the circumstance, is it normal to space out a 68mm BB to 73mm by 2x 2.5mm spacers, one on each side?

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Isn't it 2 on DS, 1 on non? Of 2.5mm spacers

You might need a 73mm "mountain" BB, rather than road. In that case you'll want 2x2.5mm on DS, 1X2.5 on NDS. Hope's doc covers variations: https://www.hopetech.com/_repository/1/documents/BSA_threaded_WEB_2023.pdf

I have no experience with Middleburn but can't you get a different spindle for these cranks?
Shimano external MTB bb's come with 3 spacers to use on 68mm BB shells. I think you can use that here as well, you could do 1 on the drive side and 2 on the nds to get the chain line better.

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Yep! https://www.mountainbikecomponents.co.uk/product/rs8-x-0003-73-mm-2/

I am currently stuck down this rabbit hole 😩

Bassi mention that this frame model has a 68mm BB shell width, hence the road BB. I think 3x 2.5mm spacers is probably the most cost-effective solution here.

Thanks for this, I’ve just placed an order! Can’t argue with that price. I’ve not opened the Spykes so may well return them.

For sure. You might need to play with the spacers a bit as the external part of Shimano road BBs are a bit wider than their mountain version, maybe 1-1.5mm. Hopefully the cranks can take up this difference. I had similar headaches fitting a pair of RO2s. Made me wish I'd stuck to square taper at the time.

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BBs aside, I'm into the rack/frame/headset colour combo.

Cheers! And appreciate the BB help, helpful to have others insights.

The Shimano mtb system is 2 x 2.5mm spacers, 1 each side to account for the 68/73mm difference and then another 1 x 2.5mm on the driveside to take the place of an e type (bb mount) front mech and you run that one with both widths.

I was under the impression that the mtb cups had a longer threaded section than the road ones to account for the spacers but @atk photo makes it look like that might not be the case.

I personally wouldn't space out the 68mm road BB cups - just not enough thread to add spacers. I found out that the hard way - new BB and BB shell re-tap required. For the cost of a MTB BB it's just not worth it

OK I might try this instead then, it’s meant for both 68mm and 73mm BB shells. Just waiting on more spacers to arrive.

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I've spaced out BBs and had no issues but, as referenced before, it depends on the length of the BB threads. The Rideworks BB looks great, and adds extra vibes. The £30 Middleburn spindle will solve any issues down the line though: https://www.mountainbikecomponents.co.uk/product/rs8-x-0003-68-mm-2/

Pretty much identical thread depths. I think I’ll just space the road BB.

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Am I too late to recommend hydro discs.

Ha, you are! But only because I folded and ordered some Deore M6100s this morning.

This makes me happy

❤️

I couldn’t say no to the £99 price from Cotic. And on reflection, I’ll just keep the Spykes and will use the IS to PM adaptors, 160mm rotors and bolts that came with them. Buying those bits separately would add up, so I’m better off storing the calipers for future use or flogging them (perhaps with the M737 levers).

Thinking more about the chainset, I reckon this nice 48/38/28 square taper triple from Spa would be a more appropriate choice over the Middleburns in terms of square taper adjustability. I’d replace the outer with a £12 chainguard and the inner with a 26t (which they can switch out gratis before shipping):

https://www.spacycles.co.uk/m8b0s109p4985/SPA-CYCLES-TD2-Stronglight-Dural-Triple-Chainset

I’m sure there’s a secondary market for the 170mm Middleburns.

The middleburns are so much nicer imo, especially with the rings you put on them

They’re in a different category to the humble Spas, no doubt. And the machining on the inside of the crank arms is really pretty. But in the context of the build as a cohesive whole, I reckon there’s something honest about ceding to a square taper BB to sort the chainline and the charmingly odd juxtaposition between hydraulics, a chis king, a wide-range ‘basic’ double clad with a chainguard and a Zipp stem… there’s also a nod to ‘ego death’ and ‘it’s just bikes innit’ in opting for Spas over Middleburns which has synergies with the 26” > 650b decision as flagged originally by Hayley.