These questions seem to cropping up quite a bit lately, so I'll jump on the bandwagon. I've got a Deore MT-62 RD and I'm wondering if I can use it to shift 8-speeds with the Shimano 8-speed bar ends. The RD is technically designed for 7-speed, but Velobase says it will shift 8 fine. Is that all I need to know? No problems here?

My understanding is that all Shimano MTB stuff 7-9 speeds has identical cable pull, so it should work fine. More knowledgeable people may weigh in, though.

EDIT: One caveat is that the bar ends must not be Dura Ace.

For the most part, there is no difference between a 7/8/9/10 speed Shimano derailleur. That's not true with really early generation Dura-Ace stuff, and some other exceptions, but its a known quantity in the cyclocross scene where they mix/match kit commonly across "speeds."

Shimano and Campagnolo - Can't We All Get Along? - Cyclocross Magazine - Cyclocross News, Races, Bikes, Photos, Videos

From that piece:

Sounds good. I'll give it a go.

FWIW, "I'll give it a go". Is always the best answer.

No doubt. If I had everything on hand I would have, but when purchases are involved, I like to ask those with experience first.

Do we have a category for transbikes?

A possible problem is the RD's inability to shift to the more inner position of the low gear. I had this issue with converting my Cannondale touring bike to 8S from 7S. This may have been due to the wider RD hanger commonly found on a Cannondale than what is normally on a steel bike. It still worked, but with the L limiting screw completely backed out.

Brad

I expect indexing trouble when using the 6 and even 7-speed SIS derailers with an 8s cassette.

Usually there is a significant problem with the indexing accuracy when the two largest cogs are selected, as the derailer does not then move quite far enough, and noise results.

I've had this problem with 105, 600 and Dura-Ace SIS derailers btw, but can't recall having this problem with your older ~MT62 Deore derailer, so it might work ok.

A strange coincidence today, after I and others posted about your using the MT62 derailer, I actually fitted a customer's bike with a larger 8s cassette and one of those old, heavy, silver SIS Deore long-cage rear derailers.

Guess what, the thing indexed the whole cassette, seeming quite well, using the bike's original 8s 105 DT levers.

EDIT: I just checked again, and the derailer is a Deore DX model RD-M650, which looks just like a later version of the MT62. So quite possibly this one was actually designed to be 8s compatible, since the DX gruppo was offered well into at least the early 90's.

Also remembering that the 8s versions of 105, 600 and Dura-Ace derailers looked quite like their predecessors, which were not 8s compatible.

Great! Once I find a wheelset I'll be in business.