You are correct, Andy, 34t cassettes were a rare commodity late-'80s/early-'90s, especially during the MicroDrive/Compact-C era. It's hard to find examples of XC Pro running that cog cuz nobody was doing it.
Joe Bernard Driving a bus somewhere in Lake County CA On Thursday, April 10, 2025 at 5:37:38 AM UTC-7 ascpgh wrote: > Hanger specs were so short, comparatively, BITD. The XC-Pro's specs were > 24mm for 28t, 26mm for 30t and 28+mm for 32t. but no hanger spec guidance > for a 34t? Disraeli Gears listed Sutherland's 6th Ed. as the source for the > XC-Pro hanger specs. That big green ring binder was a bike shop standard > but even it failed to extend the list to include what would be necessary to > work with a 34t cassette and that volume was the problem solver of the day. > > Reduced diameter drivetrains were about to come at the peak XC-Pro era and > 34t cassettes were probably out of fashion with Suntour's MicroDrive and > Shimano's > HyperDrive C about to release. > > Big headaches ensued as shops began realizing the cost of the inventory to > have spare chainrings and cassettes for all the permutations of OE spec and > local preferences on hand when this new paradigm landed. The internet > wasn't kicking yet and most options had to be special ordered given the > lack of confidence regarding which items to physically stock with no use > history. > > Piecing together our bicycle rat rod drivetrains is a bit of try it and > see. Sort of the fun of it. > > Andy Cheatham > Pittsburgh > > On Wednesday, April 9, 2025 at 7:05:53 PM UTC-4 [email protected] > wrote: > >> For the record, I'm measuring a 30mm derailleur hanger length on the >> Susie Longbolts. My 1994 Bridgestone MB3 has a 28mm derailleur hanger. >> >> -k. >> >> On Wednesday, April 9, 2025 at 4:53:22 PM UTC-5 Kirke Campbell wrote: >> >>> Andy - I love those Suntour dropouts and have often thought about >>> sourcing a pair to use if I ever get a custom frame built. And if you were >>> rocking a 34t cassette and a 26-36-46t in the front with a long cage XC >>> Pro, then I feel like I can probably pull off what I'm planning as well. >>> >>> -k. >>> >>> On Wednesday, April 9, 2025 at 9:06:31 AM UTC-5 ascpgh wrote: >>> >>>> Not an expert (Paul Brodek rest in peace) but I have a soft spot for >>>> the sunTour derailleurs especially the XC pro. >>>> >>>> The hanger specs got tight with indexing (volumes to read there amongst >>>> all the players) and the rear axles no longer had slots. >>>> [image: Screenshot 2025-04-09 at 9.06.40 AM.png] >>>> Here you can see that the axle position of these Suntour dropouts are >>>> nearly vertical, creating a fixed dimension from axle center to the center >>>> of the threaded derailleur mounting hole. That's the specification and >>>> Suntour even produced dropouts in several axle-dropout dimensions, all >>>> being within their derailleurs' ability to adjust to their satisfaction. >>>> (Johnny Coast built my rando frame with the dropout on the right with two >>>> mounting points). With a 30t-46t and 34t cassette I'm nowhere near your >>>> 40t >>>> range question though. >>>> >>>> I have used a 34t 8-spd cassette with XC-Pro long cage on my >>>> Rambouillet without difficulty butI had the TA Zephyr crank configured as >>>> a >>>> triple 26t-36t-46t, then later went wide double 34t-44t. The B-adjustment >>>> and chain length will help as will your commitment not to use big-big >>>> combination. >>>> >>>> Your chainring count and sizes additionally affect this. Makers were >>>> (still are) utterly dictatorial in the gearing combination specs so their >>>> indexing works at peak design potential. I can cope with microseconds >>>> slower response in shifting in exchange for gearing that better suits my >>>> riding needs and haven't had a problem. >>>> >>>> I added an extension tab when I wanted to run another derailleur on my >>>> Rambouillet that had 28t max and truly wouldn't clear the 34t cog. It's a >>>> friction shift drivetrain so, again, I got gearing I wanted using the >>>> french Mavic derailleur I wanted so I was OK if some shifting wasn't spec >>>> sheet precise. >>>> >>>> Andy. Cheatham >>>> Pittsburgh >>>> On Tuesday, April 8, 2025 at 7:01:54 PM UTC-4 [email protected] >>>> wrote: >>>> >>>>> Hello, >>>>> >>>>> I'd like to do something a little different on a Susie build I am >>>>> working on and am considering going with a Suntour XC Pro rear >>>>> derailleur. >>>>> Specifically, it's the XP00-GXB model, which is the long cage version. >>>>> I'd >>>>> be running this with Silver friction shifters and a Shimano 9 speed >>>>> cassette. I'm curious what the biggest rear cog I can use is? This >>>>> resource >>>>> claims it kinda depends on the length of the hanger: >>>>> >>>>> https://www.disraeligears.co.uk/site/suntour_xc_pro_gx_derailleur_xp00-gxb.html >>>>> >>>>> How does one measure the length of the derailleur hanger? From the >>>>> center of the dropout to the center of the derailleur hanger hole? >>>>> >>>>> Any real use experience running an XC Pro derailleur with a 34t cog in >>>>> the rear? >>>>> >>>>> Also, stated capacity above is 40t - anyone out there pushing that? >>>>> >>>>> Thanks! >>>>> -k. >>>>> >>>> -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/rbw-owners-bunch/e577bfc2-6db3-44d4-a339-f1fa0ddf805bn%40googlegroups.com.
