Teaching old cranks new tricks

General Help
1

Hi
I have a 26-44 crank on my touring bike and it’s not low enough. They max out on 9 speed and can’t go smaller than 26t.

I have a couple of late 80s 110/74bcd triples (Sugino VP 6sp and a Deore LX M550 7sp ) I was thinking of converting into doubles with an outer chainguard - 24-40 looks like a good combo. I have some 10sp shifters lying around so with 11-36 in the back I reckon that’d cover the right range.

Do I just buy some new 10 speed chainrings and bolt them onto these cranks? It looks like I will have issues with the chain falling between chainrings because they were originally made for 6/7 speed? Reckon I could just run some spacers tho maybe that’s too ghetto

2

The spacing of the actual crankset may cause problems in that the inner ring will be too far away from the middle ring and it will still drop in between them, this can depend on what shifter/front derrailuer combo you use, i.e. with a friction shifter can be easier to manage.

Some 110/74 bcd cranks require spacers between the chainring and the bolt threads on the inner ring, this allows you to use thinner spacers when going 10spd. I have 8spd Generation XTR cranks and they have this feature.

Would a wider range cassette be simpler? as you may find even with new rings the spacing isn’t right

Other option is a 10spd road triple and just replace the big ring with a guard and the little with a 24t ring, then you have 24-39.

3

Yeah the chain will suck right in there. Spacers should solve it, if you can make it work.

10sp compatible subcompact doubles are hard to build up cheaply. I’ve got with Campy 9sp Racing Triples on my only 10sp subcompact bike.

4

THanks for the replies

I have been using an Ultegra CX derailleur (CX70) on left friction bar-end. I have been pretty happy with it.

Any washers for the Sugino VP cranks are long gone as I have been using them 1x. The Deore LX ones have a thin spacer for the middle ring, but I just noticed the VPs have a lower Q factor so I will go with those.

My only option for a wider 9sp cassette is an 11-40 by Sunrace. I have used this cassette before however from experience using a roadlink means a lot more crap getting in my rear derailleur.

So is there no risk in using spacers? Like am I going to put too much strain on the bolt threads etc?

5

Nope, just use the extra long triple chainring bolts

6

Could you try a 9 speed sram mtb mech? Surely it would handle a better range.

7

Woah I think you’re right. I have Shimano shifters though so I’ll see if Shimano has something that handles 40t. I’ll look into this option as I do love my current cranks’ a e s t h e t i c s

This table accompanies the 11-40t 9sp cassette online:

8

If you are using a friction shifter you should be ok.

9

Friction front, indexed rear

Woah some of these shadow derailleurs are hideous

10

Alivio m4000 shadow is nominally 9sp and has a sweet barrel adjuster, goes to 36t cassette on shimano’s conservative specs

11

What Blakey said, I’ve got an Alivio m4000 and got it to work satisfactorily with a 11-42 cassette.

12

Sweet, I’ll pick one up. Woo! Easier climbs