Stronglight Chainsets

[glueman]

Impact with 46 - 34 - 24 rings. A near perfect touring set up mixed terrain on a touring bike, with a 12 - 32 rear.

[zenzinnia]

Is there much difference between the Impact and the Speedlight?

[AndyB]

Is there much difference between the Impact and the Speedlight?

They need a different bottom bracket taper (ISO, vs JIS for Impact), and have 130/74 BCD rather than 110/74 (off the top of my head).

Impact with 46 - 34 - 24 rings. A near perfect touring set up mixed terrain on a touring bike, with a 12 - 32 rear.

I agree - I run an Impact with 44-34-24 and 13-30 rear, which suits me perfectly; for less loaded I sometimes change some sprockets to get 13-26.

[PW]

The Speedlight is certainly an ISO taper. I'm running one on a Campag square taper B/B.

[CREPELLO]

It seems you've got to use the right chain with Stronlight chainsets. This has been my experience with the Impact. It doesn't have the teeth profiling or ramps of modern Shimano chainrings, for example; only a few pins. I've just removed a KMC-X993 chain from a Stronglight equipped bike because of very poor gear changes. Now, it may be the unhappy combination the chainset and this chain. I don't know if other KMC chains have the same profile, but that's the problem - very little useful sculpting of the links. The 'X' profile on the outer links appears largely superficial; there's no discernible bulge or bevelling of the edges. It wasn't that good at rear changes either, though it was a very quiet chain.

I've just replaced this with a SRAM pc971 - it's profiling looks well designed with a good bulge in the outer link. On the workstand, gear changes were largely crisp; I'm expecting the test run to be fine. Previously I've run Shimano chains with the chainset with no problem.

[reohn2]

It seems you've got to use the right chain with Stronlight chainsets. This has been my experience with the Impact. It doesn't have the teeth profiling or ramps of modern Shimano chainrings, for example; only a few pins. I've just removed a KMC-X993 chain from a Stronglight equipped bike because of very poor gear changes. Now, it may be the unhappy combination the chainset and this chain. I don't know if other KMC chains have the same profile, but that's the problem - very little useful sculpting of the links. The 'X' profile on the outer links appears largely superficial; there's no discernible bulge or bevelling of the edges. It wasn't that good at rear changes either, though it was a very quiet chain.

I've just replaced this with a SRAM pc971 - it's profiling looks well designed with a good bulge in the outer link. On the workstand, gear changes were largely crisp; I'm expecting the test run to be fine. Previously I've run Shimano chains with the chainset with no problem.

I've been running my S/light Impact with a Sram PC971 chain for about 500miles and the changes are as sweet as they were with the Shimano C/set and TA rings I had fitted before,I couldn't be happier with mine.

[drossall]

I've had a similar experience with an Ofmega crank, but never had any such trouble with either Campag or Shimano cranks.

Don't think it's a brand thing. Cranks just break sometimes. I've broken two Zeus ones (Campag look-alike, no longer made) and the odd Stronglight. Here's Jobst Brandt reporting two dozen broken Campagnolo and Shimano ones (about a third of the way down the page).

I broke the first Zeus one as a student. One of my physics lecturers was fascinated when I mentioned it (I was probably limping - I'd been last man, fortunately, in a three-up at the time). He sent me along to a colleague in mechanical engineering, who did dye testing on the other and proclaimed it sound. It broke too less than a year later.

[PW]

Regarding chains, I use 9 speed SRAM - the cheapest in the shop at the time - on Stronglight Impact and a Shimano/SRAM cassette. Never any bother and I reckon the chains are getting longer lived every time I replace one. My early 9 speeds went for 1300 miles, I'm now up to 1500+ without any cassette damage. Nothing else has altered.

[CREPELLO]

I'm just about to wield a craft knife and file to my Impact. The outer chainring has become hooked, not so much the side profile, but little sharp edges have formed at the rear edge of each tooth, which I reckon has caused chain suck and general noisiness, which isn't present on the middle ring, nor the sharp edges. So I'll smooth the teeth edges out for my England tour, then it's on with some harder wearing Dural rings at the earliest opportunity.

[cycleruk]

I'm just about to wield a craft knife and file to my Impact. The outer chainring has become hooked, not so much the side profile, but little sharp edges have formed at the rear edge of each tooth, which I reckon has caused chain suck and general noisiness, which isn't present on the middle ring, nor the sharp edges. So I'll smooth the teeth edges out for my England tour, then it's on with some harder wearing Dural rings at the earliest opportunity.

Could you turn the ring around or is it one sided due to bolt hole recesses?

[glueman]

Could you turn the ring around or is it one sided due to bolt hole recesses?

Also Impact chainrings are pretty cheap, I'd put new ones on for the effort involved, at least on the most used/worn ring.

[frank9755]

Unfortunately replacement rings for the Impact chainset are becoming harder to find, so I would be hesitant to recommend them.

I found this out as I needed a new 38T middle ring and ordered one from Spa. I asked for a Zicral so it would last longer. They sent me a ring, which I noticed was smooth on both sides. I fitted it, and upshifting from the inner ring to it was very poor. Contacting them again, they admitted they had sent me an inner ring for a double because Stonglight no longer made 38T middle rings, so this was the only 38T they could supply. I said it was no good, and they were able to send me a 36T TA middle ring in place of it. This is ramped and riveted and shifts ok (although not quite as well as the 38 owing to the bigger gap between mech and middle ring).

[drossall]

SJS seem to have a fair choice - don't they take 110mm?

[ignatzcatz]

Hoping someone can help, I run a Stronglight 57 on my retro classic Youngs but the inner ring is 44 teeth and as the rear mech is an old Campag gran sport, I am restricted to a 26 tooth bottom cog although this is a bit of a strain on the old mech. So does anyone know if a smaller inner ring was made for this chainset.

[drossall]

Well this page says it has a 122 mm PCD/BCD.

Therefore these and these (scroll down) and some more here should fit.

Usual disclaimers - no knowledge of sellers, or for that matter of your specific chainset, but hope it helps.