USCA Sidecar Forum

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Narrower front tire

Jay and others discouraged me from putting a car tire on the front of my Valkyrie and suggested a rear bike tire might be a better solution. A 150/80-17 rear tire simply isn't available. A popular replacement among Valk riders is a 130/90-17. Only about 3mm difference in radius but obviously narrower. What do you think? Will this cause any issues in handling or induce head shake? Is the 3mm difference in height enough to effect alignment? Thoughts?

3mm you will not notice, may not even be able to measure accurately. However 130 means it is 130mm wide, 150 is about 150 wide or put another way almost an inch narrower. You also need to think about load capacity with the tire. In other words is it for a bike as heavy as yours.
Jay G
DMC sidecars
http://www.dmcsidecars.com
866-638-1793

Jay G DMC sidecars www.dmcsidecars.com 15616 Carbonado South Prairie RD Buckley WA 98321 866-638-1793 Hours Monday - Thursday 6-4:30

A popular choice among Valkyrie riders who use a 130/90-17 is a Bridgestone Battlax with a load rating of 68 and V rated. At just under 700 pounds it's rated about 90 pounds less than my Dunlop E3 150/80-17 which has a load rating or 72. The Valk weighs about 800 pounds or so unloaded. I'm at 200. Escort with passenger and camping stuff may be 400 but I don't know what affect the sidecar has on the front tire loading.

Just to update, I did install the Bridgestone 130/90 and there were no alignment issue judging by the ride.  An interesting thing that happened is the "tank slappers" head shake I formally experienced at all speeds if my hand(s) were removed from the handlebars is totally gone.  I posted that on the FB website and was given this explanation for headshake.  "There are very good technical reasons why your new tyre has cured your 'tank-slapper' problems. Sidecar outfits can usualy have slow speed 'head-shake' at around 25mph, as well as higher speeds. A 'squared-off' tyre is the root cause because you are climbing up the 'raised edge' of the tyre's unworn edges and then the weight drops you back down with inertia throwing the steering the other direction. This ends up in an endless cycle called a 'tank-slapper'.  The front wheel of an outfit is the only one that really DOES need to be a rounded bike tyre, not any sort of car tyre (or worn-square bike-tyre)."

That's a lovely thought but I'm here to tell you that a round profile tire can exhibit head shake.  The usual "cures" for head shake are to tighten the head bearing and be sure the tire pressure is at least at recommended or higher.  There are many rigs that use square profile tires in front and don't exhibit head shake.

Al Olme
Minneapolis, Minnesota

Al Olme Minneapolis, Minnesota