348 replies to this topic

[chuck4788]

Racetech did some work on improving rising rate on non linkage shocks by using a true progressive spring.  The damping was compromised a bit but it did provide an improvement.

Packaging issues are easier to solve without  linkage and an off center shock.  I considered converting a XR to no linkage just to simplify, but too many things needed to be changed. With a modded, or different frame, the shock could stay in the center but attached further rear on the SA and the upper mount moved forward for more rising rate.

Edited by chuck4788, 06 December 2012 - 12:02 PM.

[chuck4788]

Along the Freeride concept I did some out of the box calculations of using a XR200 engine in a Trials bike, since I have detail weights for a Montesa 315R I used it although some newer Trials bikes are up to 20 lbs lighter.

My 315R weighs 163lbs with no fuel. the power train weights are:
engine   50.75 lbs
exhaust  7.4 lbs
radiator w/ fan  3.05
coolant 1.2
total  62.4 lbs

XR200 engine  58 lbs
stock exhaust  7.7 lbs
aftermark  6.6 lbs
total  64.6-65.7 - lbs

Forks:  19.46 lbs (CR80/85/150R) minus 15.94 lbs (315R) = 3.52 lbs
Engines: 64.6 lbs (XR) - 62.4 lbs (315R) = 2.2 lbs

So a XR200 engine and CR80/85/150R forks will add 5.72 lbs to a Montesa 315R
Add 5 lbs for a seat and the bike will weigh 174lbs.

Assume ignition, carb, and airbox weights are equivalent.

[Swiss TT Gold Member]

And all of this time I have been thinking that I could build a Freeride XR200-260 down to 165lbs...!!  HA!HA!

[chuck4788]

Swiss, on 06 December 2012 - 04:08 PM, said:

And all of this time I have been thinking that I could build a Freeride XR200-260 down to 165lbs...!!  HA!HA!

You could if you used a chassis lighter than a Monty, but the Monty has a rep for a stiffer chassis than the newer light weight bikes, or maybe their engines are lighter than the 315R.

[sixstringsteve TT Bronze Member]

bump for a great thread.  Let's keep this discussion going.

[chuck4788]

Well I'm adding a long ride seat and tank to my 315R thanks to ChrisDB selling one on TT. But that won't make a sows ear into a silk purse because the seat is not high enough for trail riding and the suspension is still only 6" of travel, just makes the bike easier on trails because you can sit a bit. IMO all of this still  makes my modded XR200 the ideal technical trail bike.
When I go riding I take both bikes and warm up for 30 minutes or so  riding the 315R on tight technical trails, then ride the modded XR on regular trails for the rest of the day.  Of course YMMV depending on where and how you ride.

Edited by chuck4788, 22 February 2013 - 06:48 PM.

[Swiss TT Gold Member]

Follow up on Brent's mention of the KTM Freeride 350 here is a TT link to the conversation including Brent's comments on his test rides and a number of really nice videos to watch.  As Brent says, probably not the ultra-bottom end bike but it shows some of its abilities in the videos.

Might have to build me an lightweight air-cooled XL/TL250 based 350 Freeride since I can't justify the $10,000 cost of the KTM!  Neat bike though!

http://www.thumperta...4-350-freeride/

Edited by Swiss, 02 March 2013 - 11:19 AM.

[Swiss TT Gold Member]

Ryder did you ever find one of the Yamaha Factory Ti shock springs on EBay for your Ohlins shock?

Swiss

[woodsryder TT Silver Member]

The stock yamaha TI spring was way too large for either the CR shock or the Ohlins,... not even close Can't remember if the spring rate was usable but I doubt it.

I ended up using an 8 inch spring length rather than the 10 inch stocker. This alone was a good weight savings but I forgot to weigh it. no problem with coil bind either. Most shocks can run shorter springs.

Edited by woodsryder, 06 March 2013 - 07:17 PM.