Tires for a 125 ????

[Mark Annan]

Hello fellow POG members.
   It is time to put fresh tires on my 1970 Sixday.  I'm looking for feedback from other people about what they have installed on their bikes.  The bike came with 3.50 x 18 rear and 3.00 x 21 front tires.  I plan to ride my bike in a variety of terrain, but mostly in soft to medium hard woods/trail conditions.  I'm hoping to take advantage of some of the newer tire designs available.  I'm not very concerned with the bike looking perfectly original.  I know that the size designations for motorcycle tires have changed several times over the years, and that their can be quite a variation between stated size and actual size.  I have seen several different size conversion charts, none seem to agree.  Fitting a front tire is not going to be a problem.  However the back is another story.  On the old steel tankers there is only 4.5" of clearance between the sides of the swing arm.  What I want to know is "What have you installed on your Vintage bike, what size,  and what are your impressions of it".  I would especially like to hear from steel tank owners.
Thanks,  Mark

 

[Larry Perkins]

Mark,
   It is hard to find a narrower 18" tire that fits well in the old Pentons.  Even with the newer Penton 100 and 125 most people run too wide a tire for the bikes good.  Besides fitting right a narrower tire allows more power to get to the ground as long as it doesn't spin too much.  This narrower tire is easier on the transmission and drivetrain too.  For just trail type riding I would consider a much maligned tire the Cheng Shen.  They make a narrow 18" tire that resembles the old Metzlers.  Before everybody goes pshyco I am not suggesting it has the performance of an old Metzler but it is decent, easy to find, and cheap so that it can be replaced more often.  If you are looking only at performance and not money for racing I think the Dunlops are hard to beat just not cheap.  The biggest problem here is that there are less and less 18" wheels.  Most bikes today that are the size of Pentons are using 17" and full size bikes mostly run 19".  If interested I have a NOS 18" HIPOINT tire that would be less than a Dunlop but more than a Cheng Shen.

 

[Chris Brown]

Hi Mark,
I put a 4.10 IRC Vulcunduro on my 175, but as Larry says, it fits in the swingarm but it's a little bigger than the bike needs. They do make it in size 3.50X18 and that's what I would buy next time. It has a really nice knob design, good rubber and much more durable than the ChenShing. It's also a lot heavier duty. You should be able to find them at a discounter for about $40 or there abouts. As Larry says, the Dunlops and Bridgestones are the choice of racers, but cost is high and I don't think it would make that much difference on our old machines.
Have fun riding.

 

[Chris Brown]

Oops. I realize I put a 4.50X18 on and should have used a 4:00X18. Hope this clarifies things...
Chris.