gene99

I currently have a Scott Plasma Pro bike - circa 2009, with a HED Trispoke front wheel and Renn disc rear.

I qualified for 5k and 10k TTs at the 2022 National Senior Games. The course is flat and there appear to be several corners/turns - some look a bit tight. I averaged about 20.5 for TTs last year and I'm looking to squeeze some more speed out of my bike.

Would upgrading to a circa 2017 - 2021 TT bike, like a Trek Speed Concept, Felt IA (1 or 3) or Giant Trinity make a noticeable difference - assuming I used my current wheels?

Also, would electronic shifting make a difference - particularly given the course turns where I expect I'll be doing a lot of shifting?

Any advice would be greatly appreciated.

Thanks.

Steve B.

Di2 on a TT bike allows a shifter to be installed on the aero bar, that eliminates getting out of the tuck to shift. Are going to be on the aero bars in tight turns or riding the brakes ?, Where are your shifters now ? End of aero bar mounted ?. Having multiple shifters is useful. Faster is questionable.

gene99

Thanks.
I'm thinking I might need to hit the brakes on a couple of the turns - and that might be multiple times/laps.The shifters on my current bike are on the ends of the aero bars. I would feel a lot better if I had satellite shifters near the brake levers. It might not mean I'll go faster, but it would keep my blood pressure lower.

Steve B.

I did a Di2 upgrade on a road bike equipped with 105 components. It was worth it as the shifting is spectacular. I've had zero issues or maintenance in 4 years, BUT it's expensive, for a standard road group, near $1000, IF you can source the parts. It's also not as worth it if you cannot run cables internally (the external routing is butt ugly IMO), as well if you have a press-fit bottom bracket, you might need a shop to remove and re-install after you feed and install cables and the B junction. I did my own install, kept the 105 brakes, crank and BSA b-bracket, the crank was part of an 11 spd system so was compatible and I was using rim brakes. I could see having satellite shifters would be very useful on a tri bike, more useful than a road bike as you can shift when your hands are at the brakes.

gene99

Thanks. The issue for me will be whether to buy a bike with electronic shifting or not. And I would certainly want to make sure it has, or could accommodate, satellite shifters.

burnthesheep

Didn't you post over on Slowtwitch?

Either way those older wheels and narrow narrow tires are tough on pavement that isn't perfect. If that bike can fit a modern width wheel like an HED "plus" of one kind or another. The newer tires, despite wider, have a better CRR than what you can find to use on the old HED trispoke. I owned one of those. I tried and gave up and sold it to a track racers. No bumps on the track. I literally owned that exact wheel setup as an intro to riding TT, it worked fine. Just was not great on anything bumpy and the cross wind on the HED 3 is tough. They sell modern tire width trispokes that have the rim profile of a modern wheel with better cross wind handling. Like the Chinese open mold Revolver Troika. You lose most aero benefit of the old HED 3 beyond a 19mm tire. Some 21mm tires would balloon up big enough to ruin the profile.

I'd say a used HED 6+ front and used HED C2 disc in the back and go 23mm/25mm staggered tire setup with whatever you can find as fastest TT tire in stock these days for that. Easy to find and setup, affordable, and known to be quick.

If those won't fit the bike, your next bet is to upgrade the cockpit to a modern setup like a Tri-rig. Then get a new fit using those neat adjustments.

Lastly, I'd get the new bike if you can't do that stuff. Just that gets costly as I would never run those wheels on a modern TT bike, they're designed around the modern width wheels.

gene99

Many thanks, burn.

I did post on Slowtwitch. All I got were pretty much wise-asrse responses.

Thanks much for your reply. I tried to mount a set of 25mm tires on the Plasma last year and the rear was too narrow. But I understand your point that even if I could it wouldn't have been very aero anyways.

Assuming I go with a newer bike but need to upgrade the wheels, do you have any suggestions? I'm certainly not wedded to disc wheels.

Again, many thanks for your reply.

burnthesheep

You missed the HED black Friday sale. I am a HED fan for the money. Their disc and 6+ front are a good combo. When not on sale mybikeshop website usually has fair prices on them. On a budget there are some open mold Chinese wheels similar to the HED but will leave that to personal research as I havent owned any like that.