I have an old Shogun (no idea what model, all tags, decals, etc have been removed) with 2x7 gearing. I want to convert the downtube shifters to STI levers but don't know if my components are compatible. I have all shimano 600 components and want to put shimano tourney A070 shifters on. Will my derailleurs work without having to be replaced?

Help a newbie out.....

As long as the shifters and cassette number of speed match, which they do at 7 speed, they will work together.

Thank you! That's what I was hoping. I've been getting warnings about spacing and everything else but, I didn't understand how that would be an issue.

I'm guessing rear drop out spacing which would only be an issue if you were going to upgrade to 10 speed or something with 130mm hub

I did that - the Tourney shifter works well. Actually, I swapped in a 7-speed freewheel for the original 6-speed, added the appropriate chain, installed the Tourney brake/shifters, and kept the Shimano 600 derailleurs. Much improved setup.

The OP says an old Shogun, how old? he says Shimano 600, which version/part #?

If the bike/gear system is pre index (which for 600 would be about 1986 IIRC) then the rear der and, if still OEM, the cog set and rings. I don't remember reading of some one who has mounted current indexed shifters with that vintage of 600 and reported their results. Quite possibly a few shifts would be fine but after that the build up of incompatibilities could be problematic. I would expect more issue with the ft der, but too few people talk about that aspect of compatibility. Andy.

I've used a Shimano 600 Arabesque Rder together with a Campy 10S shifter and a Shimano 8S cassette. Downshifts went fine, but the Rder seemed to struggle with cable drag at upshifts, so I eventually replaced it with a less used LX.
I'd assume that they are OK design-wise, but that use and age can be an issue.

The Op said the Shimano 900 was 2x7, the A70 STI's are 2x7, not seeing where any other compatibility issues could come from, on the basis that the RD/FD worked with the original 7 speed cassette, they will work with the new shifters.

For the FD, that's normally an issue with trying to mix and match between MTB and road groupsets, not an issue in this case.

Jim- Shimano has never claimed that non specific gear systems are index compatible with those that are designed with indexing in mind. The lack of this understanding suggest a youth or lack of exposure to older stuff. Nothing wrong with that except when you're offering advise dealing with the stuff you're not familiar with. There was only about 10 years of Shimano 600 prior to the introduction of indexing as it is designed currently. Now as dabac mentioned sometimes current indexed shifters will work with older preindexed ders and cogs. But I won't make any claims of this being a certainty.

When Shimano first brought out indexed systems (and they empassised the system aspect) it was made known that there are 17 design elements that went into proper performance or indexed shifting. Any one want to give the list a shot?

A real good resource for a fuller understanding of ders is Frank Berto's "The dancing Chain". It's interesting to see design elements that have been claimed by current companies were actually around many decades before. Same to for pedals, anatomical/relief grooved saddles, dual pivot calipers and the list goes on. Speedplay's pedal museum is another cool resource for those who want to learn about history and the repeating of it. Andy.

I have no idea how old the bike is. I'm guessing mid-late 90s. So not THAT old. But the components are shimano 600 RD-6400. Which are SIS and STI compatible according to velobase.com. Like I said, I'm very new at this and am just trying to get a basic bike in working order with some STI levers that function and are good quality.

I appreciate all the feedback!

More details are good. The model numbers get right to the points asked about. Only took 10 posts. As I've said many times before my replies aren't just for the OP but for the others who read and try to learn here. Usually I try to limit my replies to 3, like baseball's 3 strikes. But when there's a teaching moment I'll continue.

The first take away in this thread is to get the info complete early on. Withholding details can lead others to think you don't know what your posting about.

Here are some of the points that proper index systems are dependent on- Cog count and lever detent being the same. Diameter of the inner cable. Compresionless housing. Housing end caps with solid ends. Cable stops that the caps can nestle into. Cog c-c spacing. Ring c-c spacing. Cog or ring tooth shape (shift gates/pins/ramps). Chain plate shape and width. Der cable pull ratios. Chain lines. Pulley float and tooth profiles. Axle to rear der upper pivot/mount. Drop out pivot stop tab location. There are more but these are most of the high points. When you drift form one or two minor ones the index performance isn't too bad. drift from a bunch of minor ones and things get touchy. Drift from only one biggie and things get bad right off.

Most doing there own work don't really care to know all this. But when you're working for paying customers you better have a good grasp on the fundamentals. Andy.

The 6400-series were the first genuinely index-compatible 600/600 Ultegra group. In theory, they should play well with Tourney levers you pointed to. The bike should be OK, too, since it was apparently built with indexing in mind. (When index shifting became popular, frame manufacturers had to build to a higher standard.)

I would still clean the derailleurs thoroughly and replace all the housing and ferrules. Even one small kink can create problems that are hard to diagnose.

Funny that Shimano still offers 7-speed shifters:

Thanks. As I've said, I'm new at this. Only been cycling for a total of probably 4 months. I'm still learning, hence me joining the forum and asking questions; stupid sounding questions or not, I've learned a lot from this thread.

I appreciate it.