I looked at the United Tuni and it shows a 15" rim and then I look at the summit and it shows a 19" rim. But they both take the same size tire 20 x 2.5.

Someone help me out here. I previously thought that trials unis were always 20" rims.

The Monty 20x2.5" Bike Trials tire goes on a 19" rim. This is a bike trials rear wheel setup. The smaller rim in the rear makes for a stronger wheel, since in bike trials the rear wheel is the one that gets the most stress. Sometimes these rims are erroneously called 20" to match the tire designation which is confusing because the same company may also have a 20" rim.

For example, the Alex DX32 comes in 19", 20", 24", and 26" sizes. The Monty Trials tire will NOT fit on the 20" size, since it is a bear to put on the 19" rim.

My guess about the 15" is that it is a misprint, typo, or cut-and-paste of a typo. I may be wrong, though.

If you measure the Monty rim with a ruler, it is 15.5". Thatâ€™s where they
get the 15 from.

Darren

U-Turn wrote:

> The Monty 20x2.5" Bike Trials tire goes on a 19" rim. This is a bike
> trials rear wheel setup. The smaller rim in the rear makes for a
> stronger wheel, since in bike trials the rear wheel is the one that gets
> the most stress. Sometimes these rims are erroneously called 20" to
> match the tire designation which is confusing because the same company
> may also have a 20" rim.
>
> For example, the Alex DX32 comes in 19", 20", 24", and 26" sizes. The
> Monty Trials tire will NOT fit on the 20" size, since it is a bear to
> put on the 19" rim.
>
> My guess about the 15" is that it is a misprint, typo, or cut-and-paste
> of a typo. I may be wrong, though.
>
> â€“
> U-Turn - Vertically challenged
>
> ~~~~~~~x (ouch)
> ------------------------------------------------------------------------
> U-Turnâ€™s Profile: http://www.unicyclist.com/profile/691
> View this thread: http://www.unicyclist.com/thread/21509

lets just say that when talking about wheel sizes and inch isnâ€™t nessacarily an inch.

the actual mesurements for any given tire can be obtained by taking the stated rim diameter, multiplying it by the width of the tyre, and lighting as many candles in a pentagram shape with the width of the tyre between each candle, the diameter of the pentagram divided by the number of spokes gives you the real effective rim diameter. and the devil gets your soul.

or if you prefer to keep the back arts out of your workshop, you can refer to the spoke calculator at unicycle.uk.com
(how roger obtained all the mesurements without selling his eternal soul is a mystery to me)