Have 32mm forks on my 72 JP but also have a set of 35 mm laying around.Is it worth the effort to put these on the bike. Bike is used for intermediate trail riding no jumping. Just installed a new set of progressive shocks on the rear.
Well,,,yes and no. Barry Higgins was looking at my 73 125 before the start of an AHRMA race and told me that changing to 35mm forks was the best thing that you could do for my bike. He said he bent the 32mm forks every time he rode with them. Now I'm no Berry Higgins, but I bent mine a bunch too, and if you have a set just laying around, I'd change them.
The no part is that you will probably want to lengthen your shocks too. the 35's have an inch more travel than the 32's. I run 14 inch shocks to keep the steering head angle the same.
I've never bent 32s but I only weigh 145lbs. If you are more "normal" size and if you already have them on had, swapping wont hurt anything.
Brian
I am a fan of 35mm forks, I am building a 1974 Six Day, which was originally outfitted stock with 35mm forks. I found, back a few years ago, when I was going though many Six Day machines and racing twice a month, I found the 72-73 bike I built with 35 mm forks did handle much nicer in motocross out here in the rocky, hard packed areas in the southwest. Penton R&D decided to go to 35mm forks for a reason as they developed the better machines each 3-6 months sometimes, or that what I recall.
Just my 2 cents.
victor monz
I do have a very nice fully re-built set to bolt right on a cmf frame....whoops should be under the other forum, sorry.
Just so you know, the 32 forks are shorter and the triple clamps have less offset, which together will give you better steering control and feel for slow corners, 35s will give better suspension and stiffness.
Thanks JP for your input.
Ron Carbaugh
I prefer the sharper handling of the 32s, and they are lighter also. Those who remember the bike Tom Benolkin built a while back, he kept the 32mm forks on it. For a 100 or 125 I would never put 35s on them because of the extra weight, but for a 175 it is probably OK.
Brian
Thanks Brian and you are correct about Tom's bike. You just rotate the tubes 180 degrees after every moto. I agree with Brian especially on 100cc Pentons.
Ron Carbaugh
I always felt like the 32's had a lot of wag cornering in MX compared to the 35's but I am a good amount heavier than Brian even at racing weight. By the way Brian the 32mm forks on Benolkin's bike were bent when I got them. I much prefer the 35's on all the Pentons I built.
Larry P
Larry they were always bent. <:^)
Ron Carbaugh
If someone is interested in changing to 32mm forks, I have a good set of straightened 32mm forks I'm willing to trade for any old set of 35mm forks. And if you will kick in a couple of bucks, I'd even be willing to take a set of those worthless ribbed 35mm forks. :)
Do the 35mm triple trees fit right on the 72-73 chromoly framed Pentons?
Raymond
Down East Pentons
Yes.
Brian
Mike, what length progressive shocks do you have? And how well do they work on that JP? Also do you have the standard or heavy duty springs on them?
Raymond
Down East Pentons
When the CMF bikes came out they all had 32mm Ceriani forks but the ones that were sold in Europe as KTM had 35mm Ceriani forks.
Larry P
Hi Larry, nice to hear from you.
I bought some Hallman Racing literature awhile back and the one piece is for the Sachs powered KTM 125cc, looks to be a very early model with aluminum fenders and the early side stand pivot point. The machine is clearly being marketed as a KTM, not a Penton, and it has the 32mm forks. The literature is written in what must be Swedish and I can not read it, I looked for a mention of 32mm or 35mm in the text but I see none.
I also looked in the KTM History book by Friedrich F. Ehn and on page 108, for any of you with this book, is a KTM display of what are clearly KTM branded machines that also have the louvered aircleaner sidecover as was used in Europe, and the forks are also 32mm.
I make my fork size determination using the mounting points for the fork brace as the determining factor of the fork size as the 35mm that I am familiar with do not have those mounting bosses.
Possibly the European machines changed over to the 35mm forks before the USA Penton branded machines did, but from what I can see it looks like at least the early Euro machines used the 32mm jobs as well.
Paul
PS From what I understand the KTM history book that I mentioned was printed in either German or Italian, mine is in Italian so obviously I can not read the text, but as they say, " a picture is worth a thousand words", and this book is plum full of pictures. The link below is from eBay just provided to show what the cover looks like. I highly recommend that if you can get your hands on a copy of this book you will enjoy the "pictural history", I sure wish there was an English version.
http://www.ebay.com/itm/KTM-Weltmeistermarke-aus-Osterreich-Friedrich-F-Ehn-/131654867201?hash=item1ea73dd901:g:iTAAAOSwlV9WS71M
I'm pretty sure the early Euro KTMs follow the same production specs as those listed on the main POG page, which is to say, the '73 250 was the first bike to get 35mm forks, then in '74 everything got them.
Brian
No, Doug Wilford told me once that the bikes they received had the 32mm and the ones KTM was selling had 35mm when CMF bikes first came out.
Larry P
Interesting.
Brian