I believe that era 9-Speed RD was good for 32T cassettes, not 28,but Google (and my memory) is failing me.

---

"...the street finds its own uses for things"

The shimano RD-6500 will take up to a 28 tooth
https://si.shimano.com/...53Z0D-000-00-ENG.pdf

But it probably will take a 30 if the chain is set slightly long, meaning while in the small/small combo there is one extra link in the chain.

Really? Where?

yeah, that was the tech document i'd read. but then i read this from lennard zinn, and it made me think maybe it's worth trying a bit larger. i've found a cheap old sora online for 15 bucks, which seems like a low-risk experiment. the ultegra-level cassettes i'm finding so far are only as big as 12-27, and i think i'll want a bit more grunt than that!

but yes - i will buy a new long chain!

---

____________________________________
https://lshtm.academia.edu/MikeCallaghan

http://howtobeswiss.blogspot.ch/

i'm based in switzerland:

https://helveticman.com/?lang=en

the race looks . . . interesting. i think it's basically the norseman/xtreme-tri model applied to the half distance.

---

____________________________________
https://lshtm.academia.edu/MikeCallaghan

http://howtobeswiss.blogspot.ch/

A few years ago I was doing a similar sort of equation and came to the conclusion the best solution was to go to a triple chain set (horrific I know). On a 9 speed systems you start to get some pretty big jumps on a wide spaced cassette and that will hurt over the longer distances. You also don't want to sacrifice the higher gears for descending as its nice to have something to push against even if you aren't applying much power. Finally the cost of a NOS Shimano triple was only marginally more than a new set of front rings. The biggest hassle was tracking down the appropriate matching triple shifter although the latest generation of shimano 9-speed brifters are cheap and better than anything produced in 2004 so buying new won't be a massive negative.

I use the setup with both an 11-25 and 11-28. Cross-chaining is an issue in the granny (30) and big (53) rings. If you accidentally find yourself in small/small or big/big the bike makes a lot noise to remind you to chose a better gear but never should be in these combos to begin with. By the time you need the granny you should be well up the cassette and similarly if you are in the 53 you shouldn't be near the 25 at back.

Overall I like the triple and I definitely thinks its worth considering. Its overkill for everyday riding but a 70.3 with 3000m of climbing isn't everyday riding.

You'll most likely be OK with a 30, just make sure the chain is long enough so you don't rip off your rear derailleur.

Not sure if my memory is any good at this stage either...

Back in the day, I had a Cycle Dynamics 12x30 that worked well with DuraAce 7800. It worked with the original SRAM Force too, but the B screw was all the way out. Yeah those are 10 speed, but at the time it made me think that Shimano underestimated their rear derailleur capacity.

yeah, zinn was saying the same thing bout the b-screw . . . i can live with that!

---

____________________________________
https://lshtm.academia.edu/MikeCallaghan

http://howtobeswiss.blogspot.ch/

UPDATE:

slapped that 11-30 on the other day, and it runs very well. my first ride had about 750m of climbing and it was a relief to have that much more range. the sad part was realizing that, even at a good cadence, my littlest gear (34x30, i think) is really slow. but maybe climbing at 8km/hr is the price to pay for comfort when i'm a few hours into a long race and looking up another mountain . . ,

---

____________________________________
https://lshtm.academia.edu/MikeCallaghan

http://howtobeswiss.blogspot.ch/