Bicycle Mechanics - Pulleys: 5-7 vs 7-10 speed

In need of a new set of pulley wheels, I ordered a set with sealed bearings. They made no mention of size nor limits in use.

Anyway, the package marking suggest these were made for the 8-10 speed range, whereas my needs fall into the 6 & 7 speed category.

The pulleys come with various fitting hardware, so they fit into the vintage Campagnolo Nuovo Record RD and seem to fit well.

Is there any reason that such pulleys, made for 8-10 speed chains, should not be used with a 6-speed drive?

FWIW, the brand of the pulleys is Tacx Jockey Wheels.

6, 7, and 8 speed drivetrains all use the same size chain. I'm not sure why they would use different jockey wheels.

Should perhaps I draw the line in the sand more clearly?

The chains of 5-7 speed drives are not the same as 8-10+ speed.

So, does the pulley width count if one is using a 5-7 speed chain on pulleys designed for 8-10+ speed?

Hope that clarifies the question.

I use 8 speed chains on 6 and 7 speed freewheels and derailer pulleys all the time with no ill effects.

I think it's the 9-11 speed where you might have a problem. I'm not sure if the 9-11 speed pulleys present any problems.

I don't know Campagnolo as well as Shimano and Suntour, perhaps the difference is in whether the top pulley has any built-in play?

Are you running Campy chains and cassette/freewheel?

It's no biggie - if your jockey wheels are too narrow you can just shim the cage apart with some thin washers.

Should perhaps I draw the line in the sand more clearly?

The chains of 5-7 speed drives are not the same as 8-10+ speed.
That's not quite right. Older 5 and 6-speed chains were wider than 7-speed (and Ultra-6) chains. The 7-speed and 8-speed chains are the same width and will also work on 5 and standard 6-speed drivetrains. 9, 10 and 11-speed drivetrains each use successively narrower chains

Gentlemen,

Thank you. I'm re-building a C&V bike, a 1963 frame, with mostly 1970s parts. The rear is spread to 126, so I'm still not sure if I'll get a 7-speed in there or not. Yes, I know the Ultra freewheels are an option. But I'll start with a standard 1 3/8" chain for standard 6-speed freewheel.

The pulleys fit into the '73 NR derailleur, so I'm guessing they should work. I report if any problem emerges.

Again. Thank you.

7spd into 126 should be fine as long as you keep the chain to dropout clearance to within a couple of mm. If you're a heavier rider, an OCR might be advisable, but then you could go 8-11spd no worries in 126.

Standard 1 3/8" chain?

Duuuh. Yeah. Brain on vacation. Hey, I'm still jet-lagged.

Standard pitch 1/2 x 3/32 chain.

Kimmo: Sorry, what is an OCR?

There are 10 tooth pulleys and there are 11 tooth pullys.

seen some shimano JRA level RDs with much larger on the bottom,
perhaps for more chain wrap with a shorter cage?

If the jocky pulleys are designed work well with modern derailleurs and 10 speed chain I'm guessing that the width at the teeth is a bit more narrow. The rest of the pulley is likely "standard", whatever that might be. But if the teeth are a little narrow you may find that the derailleur has a bit more effective float in total. That being the normal float back and forth on the pivot pins as well as the chain being able to float a little more on the rollers because of the narrower jockey teeth.

As for the 7 speed setup in the back if you're willing to mess around with the spacer, cone and locknut variations with the rear you can work it so the small cog is very close to the dropout with just barely enough room for the chain to slip on and off during shifts. WIth that setup you've got the hub as far over as possible. Then use a spacer combo for the other side to fit the dropouts. Now adjust the wheel dish to fit. If the dish turns out to be TOO extreme then the idea failed. But hey, at least you tried. The key would be knowing how flat can the drive side spoke "cone" go before it becomes too easy to flop over center and taco it's heart out. THAT is one specification that I've never seen.

Kimmo's OCR stands for Off Center Rim. Some companies, I know Ritchey is one such, makes rims with eyelet holes offset to one side so that the rim can sit more to the drive side and allow the drive side spoke "cone" to have a more durable angle. Definetly something worth looking into for this build if you're keen on the 7 speed option.

OCR. Ah, yes. It didn't register.

There are some 650B rims that offer this. I have yet to receive the frame, so I have yet to measure it to see if a 650B conversion will be possible on this bike. It was built for 27" wheels, so the brake reach may rule it out. Of course, then I could just go to really, really fat 700c tires, eh? I'll still need to measure to see what brake options are possible. THEN, I will hunt for rims. The OCR design makes a bit of sense. I'm a heavy rider, too, at 225+, so the option is to be considered.

Thank you, all.