7 replies to this topic

[gliderboy TT Bronze Member]

I am the original owner of a 1982 Honda XR200R.  I have found the original IRC Vulcanduro tires to be OK but that the rear grip was a bit too much such that to get good balance and crossups I really had to get my butt up towards the tank.  Those tires are long gone and I have ordered replacements.  Coming are a Dunlop D803 for the rear and an Pirelli Scorpion XCMS 80/100 for the front.  I am not sure how the balance is going to work out.  I figure to run the very tall D803 at low pressure and to obtain a suspension effect from it to help with the XR200R suspension.  I hope that the Pirelli front tire will balance its grip well.

Any comments on this or similar combinations?

[chuck4788]

If you had too much traction with the Vulcanduro you will really have problems with the D803.
The problem with the 81-83 XR200R is short wheel base, rear set foot pegs, and high CG; but recognize that and adjust your riding style, I had to do that after installing a D803 on my 90. As a reference I have a Trials bike with a shorter wheelbase and footpegs more rear set than your XR and I climb steep hills but sometimes it seems like I'm down on the tank and bars to keep the front wheel down. Throttle control also helps.
You will learn to love the traction of a radial TT,  best tire I've found for trail riding.

[gliderboy TT Bronze Member]

chuck4788, on 14 May 2013 - 10:10 PM, said:

If you had too much traction with the Vulcanduro you will really have problems with the D803.
The problem with the 81-83 XR200R is short wheel base, rear set foot pegs, and high CG; but recognize that and adjust your riding style, I had to do that after installing a D803 on my 90. As a reference I have a Trials bike with a shorter wheelbase and footpegs more rear set than your XR and I climb steep hills but sometimes it seems like I'm down on the tank and bars to keep the front wheel down. Throttle control also helps.
You will learn to love the traction of a radial TT,  best tire I've found for trail riding.

Yeah, I hear you about the too much traction worry on the D803 relative to stock.  I was able to adjust my body position with the earlier setup to compensate so hopefully the same will be possible here.  If only I had a powroll kit to give some more thrust at the rear   After ordering my 908 rear I woke up thinking holy s$#% is there going to be enough clearance at the front of the swingarm?  It adds about 3/4 of an inch.  I think it will be OK but I may need to add some a couple chain links to move the wheel back and extend the wheelbase (probably a good idea regardless to address your point).  Did you try to mount your D803 tubeless?

[chuck4788]

I've used Nuetech Tubliss on D803s and a front knobby.  Since your XR came with an 18" rim there should be enough clearance for the slightly larger size of the D803, I've had no SA clearance issues.

[gliderboy TT Bronze Member]

chuck4788, on 17 May 2013 - 03:05 PM, said:

I've used Nuetech Tubliss on D803s and a front knobby.  Since your XR came with an 18" rim there should be enough clearance for the slightly larger size of the D803, I've had no SA clearance issues.

My original Vulcanduro is actually wider than the D803 so I know there will be no side clearance issues.  Do you think it would be reasonable to do a ghetto style tubless on the front wheeling running 15lbs pressure.  If I recall you were involved in making a super light XR200 so you may have given that some thought.  I have read extensively and know the best way to do ghetto but am not sure about pulling it off in the dirt, but the front tire is where I would want to experiment as that would benefit the most and be at the least risk of breaking the bead (I think).  Thanks for the input!

[chuck4788]

All of the newer (last decade or so) Trials bikes run tubeless rear tires, most seal the spoke nipples with a special liner.  But the rims are different than tube rims with a deeper drop center for the sealing liner, and a safety bead similar to car wheels to help keep the tire bead against the rim flange, no rim lock.  DID makes a tubeless rim without spoke nipple holes, using a flange on the rim centerline for the spokes to hook to. Tubeless tires work as I run the X11 on my Trials bike as low as 3psi  with no signs of tire slip on the rim. I seldom run the D803s with Tubliss that low, but I do go under 4psi for wet clay and see no signs of slippage.

I run a Tubliss on the front and you can run incredibly low pressures, even flat, and the tire bead stays tight against the rim flange. But no weight saving with a Tubliss on the front.

Couple of issues with a ghetto tubliss: The Tubliss "tire"  looks like a bicycle tire without tread but the bead is sized for a tight fit on a motorcycle rim.  Are there any 21" bicyle tires that will fit your front rim.
The next issue is the surface of the Tubliss tire must be smooth enough to make an air tight seal against the inside  of the knobby tire bead and the rim. The Tubliss also uses a special rim lock that fits inside the Tubliss "tire".
IMO spend the $$ and buy a Tubliss.

[gliderboy TT Bronze Member]

chuck4788, on 18 May 2013 - 09:46 AM, said:

All of the newer (last decade or so) Trials bikes run tubeless rear tires, most seal the spoke nipples with a special liner.  But the rims are different than tube rims with a deeper drop center for the sealing liner, and a safety bead similar to car wheels to help keep the tire bead against the rim flange, no rim lock.  DID makes a tubeless rim without spoke nipple holes, using a flange on the rim centerline for the spokes to hook to. Tubeless tires work as I run the X11 on my Trials bike as low as 3psi  with no signs of tire slip on the rim. I seldom run the D803s with Tubliss that low, but I do go under 4psi for wet clay and see no signs of slippage.

I run a Tubliss on the front and you can run incredibly low pressures, even flat, and the tire bead stays tight against the rim flange. But no weight saving with a Tubliss on the front.

Couple of issues with a ghetto tubliss: The Tubliss "tire"  looks like a bicycle tire without tread but the bead is sized for a tight fit on a motorcycle rim.  Are there any 21" bicyle tires that will fit your front rim.
The next issue is the surface of the Tubliss tire must be smooth enough to make an air tight seal against the inside  of the knobby tire bead and the rim. The Tubliss also uses a special rim lock that fits inside the Tubliss "tire".
IMO spend the $$ and buy a Tubliss.

Hi Chuck, I am a bit confused.  Tubliss is a commercial product that is basically a micro high pressure tube that does not inflate the tire but rather seals the bead at 100+ psi.  There is no such thing as ghetto Tubliss.  Rather ghetto tubeless comprises various methods of sealing the rim/spoke interface to prevent the loss of air there, and then allow for a tire to inflate on the rim through a bead/rim seal.  There are some high tech tapes and sealants that can be used to accomplish that objective  So with ghetto tubeless the limiting factor becomes the ability to hold a sealed bead at a given inflation pressure.  I gather that what you are saying is that is where ghetto fails!  What is X11? and are there other rims I can fit to run tubeless at low pressure.  You mention a trials oriented rim.  Would this work well for my XR200R trail bike?  Links would be appreciated.  Thanks Bro!

Edited by gliderboy, Yesterday, 07:02 PM.

[chuck4788]

gliderboy, on 18 May 2013 - 07:01 PM, said:

Hi Chuck, I am a bit confused.  Tubliss is a commercial product that is basically a micro high pressure tube that does not inflate the tire but rather seals the bead at 100+ psi.  There is no such thing as ghetto Tubliss.  Rather ghetto tubeless comprises various methods of sealing the rim/spoke interface to prevent the loss of air there, and then allow for a tire to inflate on the rim through a bead/rim seal.  There are some high tech tapes and sealants that can be used to accomplish that objective  So with ghetto tubeless the limiting factor becomes the ability to hold a sealed bead at a given inflation pressure.  I gather that what you are saying is that is where ghetto fails!  What is X11? and are there other rims I can fit to run tubeless at low pressure.  You mention a trials oriented rim.  Would this work well for my XR200R trail bike?  Links would be appreciated.  Thanks Bro!

X11 is a Michelin radial ply tubeless competition Trials tire, 4.00R18. Here is a video of why it works so well. http://home.comcast....-tire-test2.wmv

Low TP usually means tire slippage and a torn valve stem and/or the bead not staying seated against the rim flange which creates handling issue and potential rim damage.  IMO the best solution to running low TP with a tube rim is the Tubliss system because it keeps the tire bead clamped tightly against the rim solving both problems.   I have several, front and rear,  and they work great.
Bead seating a tubeless tire can be very difficult on some tube rims because of the bead differences, I have an early eighties DID rim that is a problem and two other later DID rims that are not, Slime can be your friend.

Tubeless rims used on Trials bikes are different from tube rims used on other dirt bikes; the tire beads and rim beads are different  and they don't use rim locks yet the tire beads stay against the rim flange and the tire doesn't slip.  Tubeless spoke rims use two methods to seal the spokes; one use a seal liner that fits in the rim drop center, and the DID rim with no spoke holes.

So we have tube and tubeless tires, tube and tubeless rims, run with or without tubes;  low TP or not: Too many combinations for simple answers. But to your specific question for your XR200: IMO the best option for running low TP with a Trials or knobby is with a Tubliss. Second if with a knobby get a HD tube and add a second rim lock. I have used D803s and Tubliss systems on three bikes, on one I currently run Tubliss on the front with a knobby.  The Trials bike rim is an option but the Tubliss is easier and very much cheaper.

X11 on tubeless DID rim. The low pressure is from riding wet clay last fall, I need to check pressure before the next ride.