Crankset for a single speed - help needed

[ChrisF]

A bit of help needed! I have to replace the crank set on my El Mariachi SS. It’s got a very old Truvativ GPX on it. I’d like to replace it with something that I can run a wide 1/8” chain on and would take my newish 32t 104 BCD Surly chainring when the supplied one wears out.
Also - cheapish if poss, £50-100.
I’ve looked at Deore c/sets but they seem to have a funny offset spider for the c/rings. Also, if it comes with a 12 speed chainring would that work with a 1/8” chain?
Happy to buy a new BB as it’s ready to replace.
Ta very much.

[Lazarus]

a 12 speed would work with that chain as its narrowerer than the chain - it may be sub optimal I dont know as I have never tried thin ring with wide chain[ I have used 9 speed rings with 11 speed chains without issue but that is a narrowere chain not a wider chain ] but it wi work but may wear quicker have sideways slop .
Your ring fits any crank with a 104 BCD and that is the majority of MTB cranks but sme are different [ and the deore M6100 has 8 bolts]I would need to see the cranks to say for sure

[Joe]

Can I ask why you want to run a 1/8" chain? They will fit on pretty much all chainrings because they are wider but they may flop around a bit because they are a bit too wide. If it's about strength then a decent 3/32" single speed chain should be plenty strong enough.

As Lazarus said you will just need some cranks with a 104mm bcd that don't have boost spacing. As long as it is a non boost deore chainset then the offset is probably so that the centreline is in-between the two rings. Once you take the two rings off and put a single ring on it should be in the right place.

A 12 speed chainring would work with a 1/8" chain but might be a bit floppy. You would be better off using the Surly ring straight away because they have tall teeth so your chain won't fall off and it is a bit thicker which would work better with a 1/8" chain.

[ChrisF]

Can I ask why you want to run a 1/8" chain?

I’ve got a Halo Fatfoot cog on the back that’s 1/8”.
The problem seems to be that all the Shimsno single or double c/sets I see for sale have an offset spider, ie bolt holes not at 90deg intervals. When did that change? That means I’m stuck with using Shimano chain rings I think.

[Lazarus]

yes s they do it looks a bit odd that to me.
I think the spider is replacable but that is additional faff- still running XTR M960 and M 970 - Doubt i will ever break them so think they are mine for life

[sean_iow]

The problem seems to be that all the Shimsno single or double c/sets I see for sale have an offset spider, ie bolt holes not at 90deg intervals. When did that change?

I think that's been the case since 2018? When I built my Selma up I wanted a new XT crank but couldn't get one with the symmetrical bolt pattern, in the end I used the carbon X0 I had on another (unused) bike and an aftermarket spider to take 104bcd rings.

[ChrisF]

Thanks for the info. I think I’ll go for a Deore c/set and deal with getting an aftermarket spider when the chainring wears out.

[GregMay]

eBay.... find a nice pair of Middlburn cranks and use them until the end of time.

[woodsmith]

Shimano Zee, Saint or XT and SLX triples have a 104bcd spider with 90 degree spaced bolt holes.

[lune ranger]

eBay.... find a nice pair of Middlburn cranks and use them until the end of time.

This.
I’m using Middleburn cranks that have seen almost daily use for more than 20years. I only recently needed a bearing change on the Royce BB I got with them.

[ChrisF]

Thanks all. Have ordered a Deore c/set.
Middleburn - not really a fan of this brand or of square taper BB.
Zee, XT, SLX all a bit above my budget.

[Scud]

Got to agree with Middleburn Cranks, have mine with a Royce bottom bracket, done over 20,000 miles on them in 6 years and haven't had to touch the BB, just gone through 7 chain rings, this on a Singular Peregrine.

[lune ranger]

Got to agree with Middleburn Cranks, have mine with a Royce bottom bracket, done over 20,000 miles on them in 6 years and haven't had to touch the BB, just gone through 7 chain rings, this on a Singular Peregrine.

[fatbikephil]

eBay.... find a nice pair of Middlburn cranks and use them until the end of time.

Have you seen how much middleburn cranks are going for on ebay??

I have an old school deore chainset going if of interest - oh just seen your sorted!

[GregMay]

I have not, guessing a bit then?

Perhaps I should sell my spare set?

[fatbikephil]

I have not, guessing a bit then?

Perhaps I should sell my spare set?

RS7's that have been thoroughly abused by a trials rider asking £75. RS8's are nearly as much as new ones....

[GregMay]

Wow.... ok. That is pricey