tire size

[zsnider]

So, I intend to buy a set of the dunlop 404's for my R50. The tires I have are sized: rear 4 10 - 18 ( will replace 3 50 - 18) and front 3 50 - 18. On the southwest moto website with a list of the available D404's I don't see that size designation. In an earlier thread I posted about which tires to get Marchyman mentioned running 100/90 front and a 110/90 rear in a Bridgestone tire.

Help me understand tire sizing and what size I need.

thanks Y'all

~Z

[20774]

Your bike probably requires a 3.5x18 tire front and rear. I don't know if the 410 rear tire you mention is a mistype... I thought just about all /2 bikes needed the 3.5 at both ends until the late 60s with the US models and when they changed the final drive ratio.

It would be best to find inch-size tires that are correct for the bike. Barring that, the metric size of 90/90 would be best, I think. The first 90 in the size means the nominal width is 90mm or about 3.5 inches. The second 90 means the height is 90% of the width. Inch-size tires have a 1-1 ratio between the width and height. The metric tires don't...ie, the 90% factor. But they'll work OK if you can't find the other. Due to the change in profile, the feel may not be the same and the turn in force may be somewhat different. Then again, it may not be noticeable. But the bike geometry was designed for 3.5 inch tires.

[marchyman]

So, I intend to buy a set of the dunlop 404's for my R50. The tires I have are sized: rear 4 10 - 18 ( will replace 3 50 - 18) and front 3 50 - 18. On the southwest moto website with a list of the available D404's I don't see that size designation. In an earlier thread I posted about which tires to get Marchyman mentioned running 100/90 front and a 110/90 rear in a Bridgestone tire.

Help me understand tire sizing and what size I need.

thanks Y'all

~Z

Metric vs inch sizing. What you want (but likely can not get) are 3.5 inch tires front and rear. You don't want the 4 or 4.10. What you can likely find is a 100/90 (metric for 100 mm wide and 90% of the width tall) which is pretty close to the original 3.5 inch tires. I believe Vech sells a front and rear combo (Avon?) in that size. I used the 100/90 and a 110/90 in the rear because the tire I used isn't available with a 100/90 rear.

Confusing, no?

And no, 90/90 is not the best even though the numbers might have you think that. If you compare a 3.50 side by side with a 100/90 you'll see the 100/90 might actually be a touch smaller. A 90/90 is even smaller, yet.

To further confuse things put two tires from two different vendors that are nominally the same size next to each other and you may find them different sizes.

// marc

[zsnider]

thanks that is exactly what I was hoping to learn.
The 4.10 rear tire has "will replace 3.50" printed on the tire next to the 4.10 it is an old Dunlop. I have not compared them side by side but the front and rear seen to be the same size.

Again, thanks. I going to buy some tires!
~Z

[rpeckham136133]

I have Dunlop 404's on my R50/2. They do not make the same size for front and rear, so I have the "mismatched" set...100/90 in front, 110/90 rear. It tends to horrify the purists, but I have had absolutely no issues with the tires or handling. (As a matter of fact, I am going to put 404's on my 60/6 as well.)

I replaced the old-fashioned straight-line-tread Conti front tire with the 404 and find that it handles MUCH better. The Conti tended to follow rain grooves and was skittish on a metal grate bridge that I have to cross. The 404 is much more stable.

http://bpeckm.smugmug.com/photos/355555293_SMtUa-S.jpg


PS: the back tire will be more difficult to install and take out: you will have to let air out of the tire to be able to squeeze it between the shock and final drive, but it can be done!

[44006]

www.jcw.com

C180 Street Tread Tire (SIS: 3.50x18"; RRW: 2.15; LR: 490) ZX621276P Each $70.86
$47.99
You Save:
$22.87 Will ship within 24 hours
=========================

I have used above for years on /2 and /2 conversions without
trouble - soft safe rubber easy to mount and cheap as dirt

use 3.50x18 both wheels - they are same so they can be rotated

4.00x 18 on rear has larger effective diameter which you do not
want on underpowered R50 - smaller tire has lower overall top
gear ratio

[zsnider]

I went with dunlop 404's and I got 110 /90 front and rear. I have yet to ride on them but the look tight.
~Z

[rpeckham136133]

I went with dunlop 404's and I got 110 /90 front and rear. I have yet to ride on them but the look tight.
~Z


If you meant "tight" and not "right"......? That's why I had the 100/90 for the front. You may find that the 110/90 rubs at the front. Rear on my bike has no issues.