Tire size change



41 replies to this topic
  • RMK800

Posted July 17, 2014 - 08:40 AM

#21

Best set up I've found so far for my 2012 WR is a Maxxis Maxx cross IT 120/100x18 rear and Maxxis Maxx cross EN 90/90x21 front. I've got about 300 to 400km on the pair and am very pleased. I had two very muddy races right after I mounted the tires and they gave me a lot more confidence coming into off camber corners and on slick side hills, still no complaints in the dryer conditions now.

I couldn't get the stock front tire off fast enough, it probably has 80% life left.



Do you know what the difference between the Maxxis Desert IT and the Max Cross IT?

  • torkd14

Posted July 17, 2014 - 12:32 PM

#22

Do you know what the difference between the Maxxis Desert IT and the Max Cross IT?

My buddy ran the desert IT and looking at them side by side you cant tell the difference. Maybe they use different rubber compounds or something. The desert IT is cheaper on Rocky Mountain ATV then the Maxx Cross IT for some reason.



  • cubera

Posted July 17, 2014 - 06:04 PM

#23

I like the M203 90/100-21 with a UHD tube at 10-12 psi up front. I will run other tires sometimes like right now I'm running the 90/90-21 AT81 and find it OK but a bit knifing and twitching. In back I like the Maxxis 120/100-18, Dunlop 120/90-18 AT81 RC, or 120/100-18 Dunlop 739AT, or Kenda Parker DT 80/100-21 all with a UHD tube at 8-12 psi. The AT 81 RC has a sidewall even stiffer than the 739 AT so it can run very low pressures but use two rim locks if under 8 psi consistently.  I like 13-48 gearing with stock chain length. These changes along with speeding up fork rebound some will provide for a much more :ride:  :lol: stable ride at speed especially in sand washes and over rocks and still be nimble enough for tight twisty hard pack. I'm open to suggestions still but this is where I've evolved (or devolved) the last couple of months.


Edited by cubera, July 17, 2014 - 06:07 PM.


  • MidlifeCrisisGuy

Posted July 19, 2014 - 07:03 AM

#24

 These changes along with speeding up fork rebound some will provide for a much more :ride:  :lol: stable ride at speed especially in sand washes and over rocks and still be nimble enough for tight twisty hard pack.

 

Any idea how many clicks your fork rebound is set to ?



  • MidlifeCrisisGuy

Posted July 19, 2014 - 07:08 AM

#25

Now about that front end.
Still got original tire and always wants to wash or walk over the berm when exiting. Pretty much kills your confidence to power out of a turn.
I'm coming off a rm 250 wich turn on a rail. And I know my skills are what's causing the 450 to do this. But.
Does lowering the fork height help this.
Any body have experience to changes you need to make in riding style for 250 2t to 450 4t.
Yes I know sitting on the gas cap also helps.
I

 

I had the same problem.   I cured it by installing a heavier rear spring and decreasing the rear race sag.  It made a big difference.  Huge, actually.

 

Prior to the changes, I had trouble holding lines and the front end seemed to wander.  It was always a struggle to be far enough forward on the bike to keep the front end planted.  I always had a vague feeling that I was sliding off the back of the seat of a chopper. 

 

Not any more !  Now my bike steers very precisely.  The difference is night and day.

 

Lowering the triple clamps on the forks may accomplish the same thing.  I haven't tried that.



  • cubera

Posted July 19, 2014 - 08:47 AM

#26

Any idea how many clicks your fork rebound is set to ?

 

I'm 12 clicks out but fork valving and springs are not stock. Sag is 100mm and forks are 2mm raised.


Edited by cubera, July 19, 2014 - 08:50 AM.


  • Ron W

Posted August 24, 2014 - 07:42 PM

#27

I had the same problem.   I cured it by installing a heavier rear spring and decreasing the rear race sag.  It made a big difference.  Huge, actually.

 

Prior to the changes, I had trouble holding lines and the front end seemed to wander.  It was always a struggle to be far enough forward on the bike to keep the front end planted.  I always had a vague feeling that I was sliding off the back of the seat of a chopper. 

 

Not any more !  Now my bike steers very precisely.  The difference is night and day.

 

Lowering the triple clamps on the forks may accomplish the same thing.  I haven't tried that.

 

 

Try dragging your rear brake through the corner. You'll be amazed how much better the bike stays in the berm.



  • Wounded Lobster

Posted August 26, 2014 - 03:59 PM

#28

Just whacked on a pirelli scorpion 110 on my 450. Dunno how it goes yet thanks to wrist fracture :(



  • RockerYZWR

Posted August 26, 2014 - 06:05 PM

#29

Just whacked on a pirelli scorpion 110 on my 450. Dunno how it goes yet thanks to wrist fracture :(

That's pretty good if you changed a dirtbike tire with a broken wrist.

  • Wounded Lobster

Posted August 26, 2014 - 06:59 PM

#30

Nah, I got the wheel off that was bad enough. I had the rest done for me.

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  • RMK800

Posted August 27, 2014 - 02:05 PM

#31

Just whacked on a pirelli scorpion 110 on my 450. Dunno how it goes yet thanks to wrist fracture :(


Let me guess.... Left wrist?

  • Wounded Lobster

Posted August 27, 2014 - 02:43 PM

#32

What makes you say that? Nah it's my throttle wrist :(

  • RMK800

Posted August 27, 2014 - 05:05 PM

#33

Because everybody I know including me that has broken their wrist riding has been the left. If your going down you tend to go to your left and that left hand comes out. It obviously could be either one though.

  • RockerYZWR

Posted August 27, 2014 - 06:07 PM

#34

I had a mean break on my left wrist from a street accident one time - radius and ulna both broken and popping out through the skin, it was pretty gnarly and crazy to look at my own wrist and see that (and it was coupled with a broken femur and other injuries, so it was extra uncool) - and I attribute the extent of that injury to me pulling in the clutch as I applied max front/rear braking into the truck that had turned into me from oncoming traffic.  Pulling in the clutch may be one reason why it's commonly left wrist injuries on motorcycles in general.

 

That said, I'm getting through a sprained right wrist and fingers from an arenacross accident a week and a half ago.  But that was mostly because I ran into a wall on the right side though...



  • mch

Posted August 27, 2014 - 07:01 PM

#35

A friend ordered the wrong size tire for his KTM450 and didn't realize it until after he took the old one off and he was riding the next day.  He ended up putting on the 100/90 x 19, and claimed he really didn't notice much difference.. other than everyone laughing about it.



  • Wounded Lobster

Posted August 29, 2014 - 07:35 PM

#36

I had a mean break on my left wrist from a street accident one time - radius and ulna both broken and popping out through the skin, it was pretty gnarly and crazy to look at my own wrist and see that (and it was coupled with a broken femur and other injuries, so it was extra uncool) - and I attribute the extent of that injury to me pulling in the clutch as I applied max front/rear braking into the truck that had turned into me from oncoming traffic. Pulling in the clutch may be one reason why it's commonly left wrist injuries on motorcycles in general.


Haven't heard of the clutch thing before. Broken femur takes alot of force! Can't have been fun. Did that wrist ever get back to full strength? Still have problems?

I dunno if I pulled clutch or even how I landed, all happened too fast. Was hooking up the beach and hit a little mound which bucked me straight up and off. Probably looked hilarious.

Rider in front had a go pro so you don't see the actual crash. Just me keeled over ages from my bike.

Got xrays yesterday and the radiologist said he can't see anything. Good news but won't know for sure til my doc has a better look. Been riding today and it's not much fun. Probably should give it a few more weeks.

Anyway. I'm way off topic and doin my wall-of-text thing, sorry gents.

  • RockerYZWR

Posted August 31, 2014 - 07:04 AM

#37

Haven't heard of the clutch thing before. Broken femur takes alot of force! Can't have been fun. Did that wrist ever get back to full strength? Still have problems?

I dunno if I pulled clutch or even how I landed, all happened too fast. Was hooking up the beach and hit a little mound which bucked me straight up and off. Probably looked hilarious.

Rider in front had a go pro so you don't see the actual crash. Just me keeled over ages from my bike.

Got xrays yesterday and the radiologist said he can't see anything. Good news but won't know for sure til my doc has a better look. Been riding today and it's not much fun. Probably should give it a few more weeks.

Anyway. I'm way off topic and doin my wall-of-text thing, sorry gents.

Yes, my wrist did eventually heal up and get back to full strength - twisting range of motion took a couple of years to come back fully. I looked like a 'special' person when holding my hand out to get change at a drive-thru window for awhile. That was back in '98 though, and the only really lasting quality besides the scars is a 20" titanium rod in my leg! This latest right wrist injury of mine is finally starting to feel better, so hopefully I can get back on the bike within the next week.

Glad your injuries don't seem too bad. Getting hurt and not riding sucks!

Back to tire sizes!

Two tire-related things that have piqued my interest lately are the new X-series from Bridgestone and the Baja No-Pinch tire tool. Bridgestone's M403 and 4040 are already outstanding tires, so hopefully the X will be as well! And if you haven't seen that Baja tire tool, check it out. Looks pretty nifty.

  • GP1K

Posted September 03, 2014 - 01:06 PM

#38

Now about that front end.
Still got original tire and always wants to wash or walk over the berm when exiting. Pretty much kills your confidence to power out of a turn.
I'm coming off a rm 250 wich turn on a rail. And I know my skills are what's causing the 450 to do this. But.
Does lowering the fork height help this.
Any body have experience to changes you need to make in riding style for 250 2t to 450 4t.
Yes I know sitting on the gas cap also helps.
I

 

The stock MX51s are ok, but the stock front size/profile sucks.. I switched to a 90/90 and it's WAY better. The bike handles a little quicker/nimbler, and doesn't have that wash-out feeling. That said, I'm switching to AT81s when these wear out, several of my buddies on various bikes have them now and love em.

 

The WR is a great handling bike, but does have more weight than your RM to throw around, and obviously the 2T vs 4T power differences. It will probably just take some seat time for you to get used to the difference and adapt.

 

How much do you weigh? Have you set the sag correctly? If you're too heavy for the stock springs/shock and/or your sag is off, you are probably riding 'chopper style' when sitting, which makes the bike not want to turn and/or run wide. So moving the forks isn't the answer there, getting the bike sprung for your weight and sag set is.



  • avlisj

Posted September 03, 2014 - 02:44 PM

#39

The stock MX51s are ok, but the stock front size/profile sucks.. I switched to a 90/90 and it's WAY better. The bike handles a little quicker/nimbler, and doesn't have that wash-out feeling. That said, I'm switching to AT81s when these wear out, several of my buddies on various bikes have them now and love em.

The WR is a great handling bike, but does have more weight than your RM to throw around, and obviously the 2T vs 4T power differences. It will probably just take some seat time for you to get used to the difference and adapt.

How much do you weigh? Have you set the sag correctly? If you're too heavy for the stock springs/shock and/or your sag is off, you are probably riding 'chopper style' when sitting, which makes the bike not want to turn and/or run wide. So moving the forks isn't the answer there, getting the bike sprung for your weight and sag set is.


I'm 180, 190 with gear probably. I'm on the tank, no chopper. I did find out that my sag settled. Setting it was the first thing I did but after 3 months it settled so I reset it and a little in the high side (less sag) seems to have helped.
Slip the clutch more coming out of turn. The 4t is less forgiving down low than the 2t. Think I was driving the front end out with throttle half way through the turn. Someday I'll be able to just rip through the turns without needing to slow and wack the throttle.

  • GP1K

Posted September 03, 2014 - 03:14 PM

#40

I'm 180, 190 with gear probably. I'm on the tank, no chopper. I did find out that my sag settled. Setting it was the first thing I did but after 3 months it settled so I reset it and a little in the high side (less sag) seems to have helped.
Slip the clutch more coming out of turn. The 4t is less forgiving down low than the 2t. Think I was driving the front end out with throttle half way through the turn. Someday I'll be able to just rip through the turns without needing to slow and wack the throttle.

 

Ok you're on the high side for the stock springs, but if you can set your sag ok you're probably in the ball park. Oh wait, you said *with* gear... in that case you should be fine there.

 

So what about the motor? Have you uncorked it all the way yet? What kind of FI map are you running? Maybe a little FI tuning can get the bottom end a little smoother and more to your liking? I know the bike is pretty abrupt with the just the comp ECU and base map.






 
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