ICE Sprint X Tour FS experience

[UpWrong]

I have undished a 20" rear wheel: 32-spoke XT hub, Alex X101 20mm rim, I've fitted the folding 49-406 Maxxis DTH, and an SLX HG-80 11-32 cassette. The single-wall rim is light (lighter than a DA16) but distorts easily with spoke tensions.

[UpWrong]

I weighed the rear section alone, 1590g.

[UpWrong]

Mudguard added, I'm pondering what I need to do to swap in the new rear section, and the order of attack. Will need to split the chain. Might be easiest to remove it entirely, undo the RD and rear brake cables, remove the RD, remove the old backend, fit the new backend, then install all the transmission and brake parts onto the new backend in situ, finishing off with re-installing the chain to length. I'll be changing the crankset, FD and RD so this is a lot of work.

[UpWrong]

Whilst I think of it, the photo below (not mine, from BROL https://www.bentrideronline.com/message ... ost3018341) shows how much insertion is needed for a mesh seat on a Sprint. The length shown is 455mm, I expect the corresponding insertion length is 110mm. I can't validate these measurements at the moment.

[Tigerbiten]

Just measured mine for a laugh .....
It's around 650mm ....
But cannot get more accurate due to the bottom of the hard shell on it's max recline getting in the way.
I do know I had to pull the back boom out by somewhere around 160mm for the hard shell to fit with the bracket on the upper holes.

[UpWrong]

I've started swapping the rear sections over. I've got the 26" suspended backend out, and the 20" fixed backend in. It's looking good. The weight saving is more than 2Kg. The difference in wheel weights (wheel, cassette, tyre) is 640g. The difference in the rear sections (backend, mudguard) is around 700g. Then there's the saving in rack weights which will be around 700g. Plus a bit for a shortened chain, so a good 2Kgs less total.

Still a long way to go: changing both derailleurs, refit V-brake, different chain rings, cabling, rack and adjustments.

Oh yes, the insertion length for the new backend is 185mm, same as the old.

[UpWrong]

The 49-406 Maxis DTH wouldn't fit under the mudguard, so have fitted a 38-406 DTH which is still a supple 120 tpi tyre.

[Tigerbiten]

I run a 50-406 Big Apple on the back of my trike.
If I remember correctly, there was a spacer I needed to remove where the mudguard meets the frame to get enough room to run that tyre.
Otherwise I maxed out with a 42-406 Supreme.
But I do have a very early Sprint and the backend may have been tweaked slightly in later models.

[UpWrong]

I run a 50-406 Big Apple on the back of my trike.
If I remember correctly, there was a spacer I needed to remove where the mudguard meets the frame to get enough room to run that tyre.
Otherwise I maxed out with a 42-406 Supreme.
But I do have a very early Sprint and the backend may have been tweaked slightly in later models.

I considered removing the spacer but I reckoned it needed longer stays too. The 50mm BA is undersized, the 49mm Maxis DTH is actually wilder.

I have the V-brake recabled after shortening it by around 9cm.

[UpWrong]

That was my weekend. Still not complete. However, new FD and RD installed, return chain tube shortened by 3", 26/36/48 chainrings fitted to cranks, chain reconnected in small-small and left slightly long for now (will see how it looks in large-large). I didn't remove the chain entirely, leaving it in the drive side tubes throughout. Half wish I'd fitted a new, clean chain but that would be wasteful with only 1000 miles tops on the current one. Still need to cable up the derailleurs and adjust, and sort out a rack but it's looking good.

[UpWrong]

Decided to weigh my Sprint. All the bits are present apart from a rack. I used the bathroom scales and 2 piles of magazines method:
front left 7.0 Kg, front right 7.2 Kg, rear 4.4 Kg, total 18.6 Kg (41 lbs)

Changing the M+ tyres on the front to Racers would bring it down to 40 lbs. The titanium rack and stays will be around 0.5 lbs. I could lose that by changing the granny and middle rings from steel to alloy, and by losing a couple of stays from the rear mudguard. I may not bother.

[UpWrong]

All done, though I shall retrue the rear wheel after a couple of rides. FD was tricky, had to raise it to stop the cage hitting the middle ring when trying to change to the outer ring. Cabling up the RD was a challenge to pull the cable tight whilst tightening the clevis nut which twisted with the applied torque. Removed a couple more chain links and capped all the cables. Reckon that was 4 days work total to change back ends but I do take my time to get things right. Hopefully a test ride this evening.

[UpWrong]

15 mile ride last night, no problems. The turning circle is noticeably smaller. The trike felt lighter and more sporty in terms of responsiveness and handling. The ride was mostly acceptable with some jolts that were felt by my neck. I had the M+ on the front at 70 psi and the Maxxis DTH on the rear at 55 psi.

[UpWrong]

A second ride with the rear tyre at 50 psi still felt "jolty". It seems to be gaps in road furniture or jointed concrete that have the most abrupt effect. Frost damaged country roads aren't the problem generally. The handling through curves and bends is so much better with the small wheel.

Having thoughts about fitting that bigger 49mm Maxxis tyre. I'll need to sort out some longer stays, so I might try to reduce their number from 6 to 4 at the same time.

[squeaker]

The handling through curves and bends is so much better with the small wheel.

And the rigid rear end? Lots of things going on with this change! I look forward to more reports