chobbs77

I am interested in upgrading my derailleurs on a 2x7 bike. I have been looking online and can’t find any 7 speed rear derailleurs. Can I use an 8,9, or 10 speed derailleur on a 7 speed cassette?

fietsbob

the actual; derailleur has no "speeds", it just moves inward as pulled by the cable ..

chobbs77

So what does it mean when the website calls it a Shimano ten speed derailleur?

philbob57

Do you want indexed shifting?

I can tell you that my 5 speed-era Suntour V-GT has the range necessary to shift a 7-speed freewheel without a problem. I'm having trouble indexing it, but I think it needs to be cleaned, and I'd rather ride than clean.

chobbs77

I think I understand what I need to do know. My shifters and cassette have to be the same speed to be compatible. So I cannot use a 9 speed shifter with a 7 speed cassette, is that correct?

Bill Kapaun

I just Googled 7 speed rear derailleur and had no problem.
What do you currently have? It may be better than what's available now???

shelbyfv

Yes. Cages can have a little less clearance as you go up in speed so if you want to continue using the inexpensive 8 speed chain you might be better off with an 8 or 9 speed RD. Obviously 11 speed won't work and I think 10 speed mtb is wrong as well.

Oneder

I would get the 8 speed anyway then you can upgrade. You can use it in spite of not being 7 speed. Wish I had been thinking ahead last time I replaced parts because I could have gotten 8 speeds and gotten wheel later.

70sSanO

I guess a couple of first question is what do you have now? And why do you want to upgrade?

I think the assumption is that you have an inexpensive bike, but for all we know, you have an 80's Colnago and want to go to a 7 speed index drivetrain.

The general answer is any 7/8/9 series rear derailleur will work. Up to 10 speed, Shimano rear deraileurs were backward compatible as far as indexing. Non-index derailleurs are another thing. Front derailleurs are another topic between road and mountain.

The truth is 11/12 speed systems give more performance because you can gap the gears more efficiently. The real benefit is with 1x drivetrains. The other truth is that no manufacturer is putting their money into 7/8/9 speed systems other than to support the lower end bikes and older pre-owned bike market.

So if you let us know what you would like to do, there are a lot of people who can help you go in the right, or many, direction(s).

John

chobbs77

I am getting an 80’s Trek pro series. It has older Shimano 105 components on it, can I upgrade to brifters without getting new derailleur?

fietsbob

Worth a try.. Eh?

fietsbob

That means it's recent production..

the warehouses selling to bike shops (for repairs) may have older parts left on the shelf , having bought big getting best prices,
where the online sellers turn over smaller orders more often, feature stocking for the latest parts..


..

70sSanO

If it is indexed now, you can go to brifters without an issue. But... current 7 speed brifter quality is not very good. If your freehub accepts hyperglide cassettes, I "think" 1989 had a UG/HG freehub body, then you can easily find a current Hyperglide cassette that will work.

This might be a solution for slightly better brifters. Claris is 8 speed and Sora is 9 speed. You can get an 7 speed cassette and, break it apart, sand the spacers to 3.0mm, and run an 8 speed Claris, which is not terrible, with your re-spaced 7 speed cassette. You will only get 6 clicks and 7 speeds but it will work. You can probably do the same and space to 9 speed and run Sora, but I don't know if there is enough of a quality upgrade to run maybe 8 of 9 speeds on a UG/HG. I've never done 8 of 9 on a 7 speed cassette freehub body; but Sheldon Brown says you can.

There is one last piece to this... With a UG/HG freehub body, you might be able to squeeze out a tab more freehub body room if you use a threaded Uniglide 1st position cog. You can use it with a Hyperglide cassette. Depending on how many teeth you want, you can find a 34.6 threaded 1st position cassette cog on eBay.

John

chobbs77

The current wheel has a 6 speed freewheel, but I have another wheel at home with a 7 speed cassette. Should there be enough space in the frame to put 7 speed on?

shelbyfv

We are going in circles here. First it was upgrade the derailleur, now it's the shifters w/o the derailleur. Any of this is possible but you need a plan before you start. I suggest you actually take possession of the bike and assess the condition of the components. You'll be better able to decide which path you want to take.

chobbs77

The derailleur was for my 1987 Peugeot Triathlon. I asked the question about the cassette since I found this Trek bike for $60. I figured that the Trek would be a better bike to upgrade to current components.