Cycling UK Forum

I'm upgrading my wifes 8-speed MTB to 1x11 speed and so far have the shifter, mech, chain and cassette. Its got an old 94 BCD 5 bolt triple chainring and I can't decide whether to replace this with a modern single speed chainset or just buy a new compatible chainring. There are few narrow wide options in 94 BCD 5 bolt but they are pricey, as expensive as a new chainset.

Standard chainrings in this pattern all seem to be 9 speed but only £30-35. She won't be doing any extreme riding so I wondered if I would get away with just a new standard 9-speed chainring, likley a 30T one and add a chainn guide if there are problems with dropped chains.

All feedback welcome or pointers to 10-11 speed 94 BCD 5 bolt rings that I've not seen

I use a stainless steel surly chain ring with my 1 x 5 transmission. The teeth aren't thin/thick but one uniform width, however the teeth are longer [than a usual size chain ring teeth] which helps with chain pick up and stops the chain from coming off...
Charlie the bike monger has some in stock with a 94 bcd.

However you may have to check to see if the chain ring is too wide for an 11 speed chain.

Thanks I've seen the Surly ones at a few online shops so will check that out. I'll likely need shorter chainring bolts too. Have to see how it adds up. Existing chainset is silver alloy so that Surly one would look nice. There are similar TA options too.

According to the measurements that Surly give on their website, the teeth on their stainless steel 94BCD chainrings are going to be too thick for an 11-speed chain to fit. They say:

NOTE: 94mm BCD, 104mm BCD, and 110mm BCD x 34/35/36t chainrings are made with a 2.2-2.3mm thick stock plate and they work best with 5- to 8-speed chains. The 110mm BCD 38-50t and all 130mm BCD chainrings are machine finished to have a 2.1mm tooth thickness and will work fine with 9-speed chains.

When I use a good pair of vernier calipers to measure the inside distance between the inner plates on a couple of 11-speed chains (one KMC, one Shimano), I get 2.12 mm, which is less than the tooth thickness Surly quote for their 94BCD chainrings.

You could just use an ordinary 94BCD chainring and fit an old front derailleur over the ring with the stops screwed down to prevent the chain derailing. That's what I did on my touring bike, where I retrofitted a Rohloff hub and had to use the chain tensioner as the bike has vertical dropouts. Without the FD there, the chain would occasionally come off over bumps. With it there, the chain has never derailed. p.s. Wolf Tooth make 94BCD 5-arm N-W chainrings, but they're not cheap: https://www.wolftoothcomponents.com/pro ... arm-cranks.

NickJP wrote: ↑30 Apr 2022, 5:55am . . .
p.s. Wolf Tooth make 94BCD 5-arm N-W chainrings, but they're not cheap: https://www.wolftoothcomponents.com/pro ... arm-cranks.

Thanks for the advice, I may just try it with the existing 8 speed rings to start with and see how she gets on, get my vernier calipers out
Did see the Wolftooth rings but just too expensive for this build, they would make sense with a more expensive older chainset though. I think I'll end up getting a modern chainset in the end.

Daipink wrote: ↑10 May 2022, 7:13am Thanks for the advice, I may just try it with the existing 8 speed rings to start with and see how she gets on, get my vernier calipers out
Did see the Wolftooth rings but just too expensive for this build, they would make sense with a more expensive older chainset though. I think I'll end up getting a modern chainset in the end.

As you said earlier in the thread, I would add some sort of chain guide to be sure… Either the FD fixed in place with the H/L screws. Or a inner and outer guide. Nothing worst than a dropped chain, particularly if out the saddle…. Ouch…

I guess you may have bought the 11-speed kit already, in which case this is irrelevant. But if not, and as you seem not to want to spend too much, I'd consider a less radical alteration to 2×, as this deals with the main reason people find triples "too difficult/complicated/unreliable/whatever". When you probe deeper, the main problem with triples is the middle to inner shift sometimes/often just won't happen. And when you probe deeper still it's a wonder that shift ever happens at all: the front mech is too far above the middle ring to slice the chain neatly off it. Doubles don't have this problem - not at all. Front shifting never really ought to have gone beyond doubles - although triples where the middle ring is only a few teeth smaller than the outer (to provide in-between gears on a wide-range of not-many rear sprockets) also shift reliably.

A sub-compact double is also less complicated to think about. To all intents and purposes it's a 1× with the option of shifting to the inner when you see a really steep hill coming up. That works really well when you create such a double simply by using the middle and inner positions of a triple crank. Because the middle position, now your outer ring, lines up near enough with the middle of the cassette to use all the sprockets efficiently - just like 1×. Because this is now your outer ring, you can slide the mech down the frame so it's now nice and close to those teeth and can shift the inner reliably, even when you can't ease up on the pedals because you're on the hill you want it for already! Depending on what size middle ring you've bought for use as your outer (you can get middles as big as 40T for the 94mm BCD), you might need to swap your triple mech (because the back end of its super-deep cage now fouls the chainstay) for a purpose-made MTB double mech.

Don't worry about having a bigger drop to the 22T inner, it'll generally work fine. I have 40,20 on one of my bikes, and it shifts even better than the 42,26 on another. Although the chain falls a shorter distanceon the latter - well within specification - it did sometimes miss. So on that bike I fitted a Jump-Stop, which is easily done if you need to and puts an end to all worries. The 40,20 has never missed a shift however, so even though I've got a drawer full of Jump-Stops, I've never fitted one to that bike!

With two rings of something like 38,22 - you may well find that an 11-32 8-speed cassette still provides all the gears your wife needs. Worth a try perhaps.

A new 94bcd crank, will probably show up under other names.
Soma aka Merry Sales is large distributor in the States, so this would be a Taiwan forging.

https://www.somafabshop.com/shop/produc ... tegory=759

Thanks all for advice, and from so far afield! As CJ guessed I did in the end buy the 1x11 kit, rear mech, shifter, chainset, chain and cassette. I got lucky as well in that I found an old pair of budget Bontrager wheels would take an 11 speed cassette where a newer Shimano hubbed set wouldn't. Here's a pic below of it set up with the 11-42 cassette of my 29er temporarily. It's now got an 11-36 on it and some WTB riser bars which came off an early 00s Kona Kula which I plant to re-build. I may go for 2x11 on that and my old Kona AA as will probably do a mis of road and off-road on those, if I ever get them completed! Thanks again all.

https://photos.app.goo.gl/pEvwM8Vh11LTzytCA

jdsk how do you do that?

Your previous outlink was to a Google Photos page containing the image of interest. But also containing navigation elements etc. This site can't spot that what you're trying to do is only show the image. What you need to do is find the URL of the image itself.

So I *did that and then added an outlink on this site to the image. Now it shows inline.

Jonathan

* I use Safari on a Mac.

Thanks I tried a few different ways but it couldn't get it to show up in the preview

Jdsk wrote: ↑30 Jul 2022, 3:45pm Your previous outlink was to a Google Photos page containing the image of interest. But also containing navigation elements etc. This site can't spot that what you're trying to do is only show the image. What you need to do is find the URL of the image itself.

So I *did that and then added an outlink on this site to the image. Now it shows inline.

Jonathan



* I use Safari on a Mac.

If you'd like to experiment with getting this working:
viewtopic.php?t=152407

See you there.

Jonathan