Rim and tire sizes (yes, AGAIN!)

Unclviny · Sep 29, 2010

Folks,
I was going to run WM4 X 19" shouldered Morad rims with 100/90 X 19" Avon Roadriders front and rear but the rims seem to be unavailable (I tried Gearhead Racing, Buchanans, British Cycle Supply and Central Wheel), the real problem is that Morad makes the rims but no one wants to order them for me!

So on to "plan B" WM3 X 19" rims with 3.25" X 19" Avon Roadriders front and rear, the tires (tyres) seem a bit on the "narrow side" but at least I will not have clearance issues.

Can I get some "real world" width measurements for different tire/rim set-ups? (I think a 3.25" is 3.9" wide but I want to make sure).

Vince

Hobot · Sep 29, 2010

Basic tire reading charts.
http://www.amadirectlink.com/roadride/R ... /tires.asp

Here's review to ball park the range.

Ben English wrote:
>
> Those are straight equivalents in all the size charts I've seen.
>
> << Has anyone else run these narrower sizes
> 3.7" in place of 4.2" for the front and 4.5" in place of 4.8" for the
> rears >>
>
> How do you get these numbers?

For the Front (AM20 RoadRunners)(Avon's web site)

3.25-19 OAW 4.2 inches; OAD 26 inches; rev/mile 343; Max load 467 lbs
90/90-19 OAW 3.7 inches; OAD 25.5 inches; rev/mile 318; Max load 441

For Rear (AM21 Roadrunner)
400-18 OAW 4.8; OAD 26.5; Rev/mile 307; Max load 617 lbs
110/90-18 OAW 4.5; OAD 25.9; rev/mile 313; Max load 567 lbs
120/90-18; OAW 4.9; OAD 26.5; rev/mile 307; max load 639

Rear Bridgestone BT45 (what I'm considering) (Firestone web site)
110/90-18 OAW 4.3; OAD 25.8; Max load 567
120/90-18 OAW 4.8; OAD 26.5; Max load 639

Rear Metzler 99A converted from mm(what I have now, which just clears
rear master cylinder)(Metzler web site)
400V18 OAW 4.5; OAD 26.2; Max load 617

Granted these could be measured on different rim widths.

OK writing this I'm going as planned (90/90 front; 110/90 rear)

>
> Using the handy catalogs from my favorite tire maker, Avon, we get these
> numbers:
> Front, both on WM3 2.15" rim (Your T140 front wheel is most likely WM2
> 1.85")
> 3.25-19 Speedmaster width = 3.4"
> 90/90-19 Roadrunner AM20 width = 3.9"
>
> Rear, on 2.50" rim (You probably have WM3 2.15")
> 4.00-18 Safety Mileage Mk II width = 4.4"
> 110/90 Roadrunner AM21 width = 4.5"
>
> Other brands and models will vary in actual measurements but not in
> general relationships. To sum up, these are exact equivalent sizes, but
> modern metric measured /90 series tires will generally be a bit wider
> than equivalent traditional inch sizes, as we see in this case.
>
> Ben English * Albany * New York * USA
>
>

Fullauto · Sep 29, 2010

Hi Vin,
I think that Morad don't do the WM4 rims valanced. In fact, I don't think I've ever come across anybody who does 19 inch x 2.5 inch in a valanced rim. 18s no problem. I run the unvalanced ones in 19 inch with 100/90 Roadriders and I think they look good and they certainly enable you to use all the tread, unlike the same tyre on the standard WM2 rim. The 2.5 inch rim is what Avon recommend for the 100/90 x 19 Roadriders so I would stick with that. In order to gain clearance for the tyre at the front, I merely replaced the guard mounting bolts with button headed stainless cap screws. If you don't, the tyre simply won't squeeze past. On the rear, I had to turn the lower shock mounting bolt around so the narrow head was to the inside, otherwise the same problem crops up.

With mine set up this way, the steering is an absolute delight with no wobbles and nice light steering.

splatt · Sep 29, 2010

I tried to do this a while ago, I saw Buchannans listed a 19''40 hole wm4 in Excel non flanged, plus also their own brand,all to easy I thought, but as they don't answer their emails I havn't been able to do a bloody thing, hub has been sitting at wheel builders all winter, any one deal with buchannans on a regular basis.

Unclviny · Sep 30, 2010

According to Central Wheel Morad does make them but the minimum order is 10 rims and I only want 2.

Mark at British Cycle Supply says that he has never seen one!

I really want to run shouldered rims and I like the 19" rim "look" so:
I think I will go with WM3 X 19" shouldered rims with 3.25" X 19" Roadriders front and rear, according to Avon the 100/90 X19" tires are 4.3" wide and the 3.25" are 3.9" wide.

The best handling bike I have ever ridden was my 1973 850 Commando with 4.10" X 19 Roadrunners front and rear on WM3 rims (with slightly tighter than spec Iso's).

Vince

Rim and tire sizes (yes, AGAIN!)

Unclviny

Hobot

Fullauto

splatt

Unclviny

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