New Synergy rim with Pari Moto tire

[dailyrandonneur]

I need the group's input on a problematic install of Pari Moto tires on new Synergy 650b rims.

The tires were mounted without any problem on an older set of the same model rims, from 2008-2009.

On the new rims it's pretty obvious the well is deeper. With one layer of cloth rim tape the tire had big hops.

A second layer of rim tape helped, but I still get a spot where the bead line disappears. I've tried talc on the bead and working the tire up under low pressure with marginal results.

I'm using Kenda 559 1.5-1.9 tubes. Should I size up? Or just get it as good as I can and go ride?

thanks,
Ed
Washington, D.C.

[Steve Palincsar]

Have you tried hand-manipulation to better seat the bead?

[Rick Johnson]

You might consider trying tubeless rim tape instead of cloth. It's
thinner than cloth - giving you the ability to fine tune the thickness
on multiple layers. It's also more slick than cloth which should help
allow the bead to slide into position easier (similar effect to the talc
you tried).

Rick Johnson
Bend Oregon

* * *



On 6/17/2013 8:35 AM, dailyrandonneur wrote:
> Synergy 650b rims

[Edward Felker]

Mysterious. I tried a new black Pari Moto on the same rim and it mounted without any problems.

So there was something about the tan sidewall versions that I was using -- original production from when Kirk called for advance purchases to get them made.

[Fred Blasdel]

On Mon, Jun 17, 2013 at 8:59 AM, Rick Johnson <rickcj...@gmail.com> wrote:

You might consider trying tubeless rim tape instead of cloth. It's thinner than cloth - giving you the ability to fine tune the thickness on multiple layers. It's also more slick than cloth which should help allow the bead to slide into position easier (similar effect to the talc you tried).

Unless he wanted to use a mile of it, he'd need to use it *on top* of cloth 

[Rick Johnson]

Unless he wanted to use a mile of it, he'd need to use it *on top* of cloth 

Fred,
I suppose that would depend on the final thickness desired. Stan's yellow tape is 6mils (~0.153mm) thick which would give a fine graduation to the buildup. But needing a mile of tape might be overstating it a tad.

1 mile is ~1609m, which would yield about 874 wraps on a 650B rim. With Stan's yellow tape that would be about 133mm thick and result in a final rim diameter of around 850mm.

Rick

Rick Johnson
Bend Oregon

*    *    *

[Jon Doyle]

I used Tressostar handlebar tape over a layer of gaffer's tape in my Synergy rims, taking cues from Jan Heine's post on the subject: http://janheine.wordpress.com/2012/05/24/mounting-tires-on-rims-with-deep-wells/. Results have been good with Hetres; the tire definitely gets into the correct position with less work.

Jon

Watertown, MA

[Rick Johnson]

An astute reader noted a flaw in the tongue in cheek portion of my reply to Fred - that my calculations didn't account for the increasing radius of the wraps or rim tape.

Well, I was thinking about that while riding the other day and a few Excel formulas solve the problem easily. Auto Fill makes taking this calculation to a ridiculous extreme easy.


So Bruce, here's what a mile of 6mil rim tape can do on a 650B rim:

Wraps

Diameter (mm)

Tape Thickness (mm)

Wrap Length (m)

Tape Total (m)

0	584.0	0.153
1	584.3	0.306	1.835	1.83
2	584.6	0.459	1.836	3.67
3	584.9	0.612	1.837	5.51

735

808.9

112.608

2.540

1607.81

Rick Johnson
Bend, Oregon

On 6/18/2013 5:36 AM, Bruce Herbitter wrote:

So now I want to see the formula calculating the wraps and accounting for the constant change in radius.....

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[Bruce Herbitter]

Good stuff Rick!   Here's a handy link as well:

http://www.giangrandi.ch/soft/spiral/spiral.shtml