Originally Posted by
70sSanO
I wouldn't hold your breath until you understand exactly what SeattleJG was using in the first place.
To start off with, Trek made 2500, 2300, and 2100 frames in 1991. As far as I can tell they are the same frame with the only difference being the component group. By 1991, "most" mfg were making their high end frames at 130mm, but at the very least 128mm so they could accommodate either a 126mm or 130mm OLD.
The 1991 2500 came with 8 Speed Dura Ace, 7 Speed Ultegra, and 7 Speed 105.
Case in point, I have a 1991 Specialized Allez Epic of similar construction with 7 speed 105. It came with 8 speed Dura Ace, 7 speed Ultegra, and 7 Speed 105.
The 8 Speed Dura Ace is 7403 and has an OLD of 130mm.
If I measure the top of the dropouts I'll get 126mm, but where the dropouts slide it is 128mm.
I have no clue what freehub or freehub body is on SeattleJG's bike. I'm somewhat skeptical that after 30 years of people converting from 7 speed, that the fix was as easy as using a CS-6700. And he is the first person to discover this. There is no knowledge if the original freehub body was ever replaced somewhere along the line. The only way to tell is to measure the length from the cassette stop to the end of the freehub. It is also a tough sell that a 1991 UG/HG freehub body can accept an 11t since there is no relief for that size cog. I'm guessing the freehub body was replaced along the way and a spacer was placed behind the 7 speed cassette and it fits into the frame because it is 128mm.
But if it is true, it is great news and I hope no one tells miamijim that his effort was a waste.
Many late 80's/early90's bikes, maybe even the Klein Performance, were made with 128mm dropouts. If it has a 7 speed freehub body, I have my doubts you'll fit a 10 speed, but it is possible to replace it with an 8-10 speed body... been there, done that.
John
Firstly, thanks, SeattleJG (and CB400bill).
Ok, for starters I did mention 1992 as the date by which virtually all road frames were made to 130mm. My own Klein Performance date-codes to late 1989 and is solidly at 126mm and with Ultegra hub measuring same.
All of my road and mtb 10s cassettes have their rear mounting surface recessed about 2mm from the face of the largest cog, positioning the cogs that much closer to the hub centerline.
I grabbed several 7s wheels to test out with my 12-30t 10s Ultegra cassette and fitted the cassette to all of them.
All four hubs gave more than 3mm clearance from the face of the smallest cog out to the serrated locknut teeth on the axle.
The modest HB-RM40 hub (a later model perhaps?) is the best candidate of these four 7s freehubs because of it's having the best/most purchase with the splines of the smallest cog (
it's splines are not threaded for UG cogs).
The Hyperglide-C hub fared the worst in that regard because the ends of the splines are shortened significantly, but it still engaged the splines even before I secured the lock ring.
The other two hubs (105 and Ultegra) both had UG threads cut into the end portion of the splines, which somewhat reduces their load-carrying area (if perhaps not as bad as the shortened Hyperglide-C freehub body).
A steel lock ring must be used, because of the minimal threading engagement with any of these hubs. There is not much more than one turn of engagement, but thankfully the freehub bodies here are all steel instead of aluminum.
There are steel lockrings from other brands having a bit more threaded engagement than Shimano's.
My own lock rings from IRD, SunRace (and even a Shimano-compatible Suntour specimen) all appear to have longer threading.
A down-sized 11t steel lockring seemed pretty good as it nested into the 12t smallest cog, adding another half-turn of threaded engagement (this is the lock ring used in my photo below on the Klein's 7s Ultegra hub).
Again though, there is a full 3.5mm of locknut protrusion out past the face of the smallest cog! Amazing.
Ok, all fitted up for testing and the derailer cage appears to still have 2-1/2mm of clearance to the spokes.
The top pulley bolt was ticking against the spokes, but only because some buffoon (me?) fitted Bullseye pulleys that weren't spaced out quite the same as the originals.
Still using the original 7s chain and shifter, and it indexed nearly ok during the trip across the 10s cassette (after I backed out the lo-limit screw two turns). Clearance to the dropout is adequate even with this 7s-width chain.
One more thing is that I do worry that this arrangement might suffer material failure in the area of the smallest cog if used under hard conditions of smaller chainrings and/or heavy loading while using the small cog.
Bigger, harder-riding riders with smaller chainrings in hilly terrain beware! Failure could lead to crashing and death.