Front tire usage

[Dsheumaker]

So I am running an 09 250, have the gsxr rear shock with the linkage to bring the rear up a little higher than stock, racetech springs and GVEs up front, I am running the Dunlop alpha 13s. On the rear I have about a 1/4-1/2" left of un-used tire but on the front I am all the too the edge. What causes this? IS there a setup change that would help fix this? Like I feel like I should be able to lean more than I am but running out of front is a little discouraging. My body positioning is very exaggerated, so my bike stays as upright as I can keep it. Thanks for any help.

[Sirref]

This is normal for the Alphas. The tire is a stiff carcass and our bikes don't put down enough power to compress the rear tire on exit (the RC390 does, barely)

It's a regular thing when you go up sizes in the rear as well. As for being able to lean more, I don't know these bikes don't lean at the absolute limit like the supersports can in the right hands

[RacinNinja]

With the wider rear, you probably won't use all of the rear tire. I'll get some pics of the difference between the front and rear of mine later tonight.

[Dsheumaker]

Yea I get thst I won't be able to use all of my rear but I guess I'm looking to see if there is some type of adjustment thst I can make that would use less front haha

[RacinNinja]

Run a 120 series tire. Alpha's are 110 and only come in 110 so you'd have to find something to match it with.

[Dsheumaker]

Damn. I love the alpha and the price of the alpha

[RacinNinja]

Or, forget about it and just ride. I'm fairly confident you could drag peg and not run out of tire. Provided your pressures are correct, the front will flex and you won't run out of tire.

[AwDang]

What he said

It's normal. 5' kiddo getts knees down and has the same wear description

[csmith12]

Are your sag numbers even close? If not, I would start there.

Next, iirc... didn't you have this issue before or needing to replace 1 front to 1 rear tire? Also, didn't you have a heavy brake riding style? That style will lend itself to heavier wear on the front and normal for those styles of aggressive riders.

Sounds like it's time for a baseline suspension/geometry setup and then start tailoring it to your personal needs.

After you have it set, you may find that it turns a bit slower than your current setup. If so, try a 90 in the front to get your flick rate back to what it was. You might even find that you like the profile of the sc1 90 on the front and rosso II 140 on the rear. Best bang for buck for fast paces on a 250 imho.

[Dsheumaker]

Originally Posted by csmith12

Are your sag numbers even close? If not, I would start there.

Next, iirc... didn't you have this issue before or needing to replace 1 front to 1 rear tire? Also, didn't you have a heavy brake riding style? That style will lend itself to heavier wear on the front and normal for those styles of aggressive riders.

Sounds like it's time for a baseline suspension/geometry setup and then start tailoring it to your personal needs.

After you have it set, you may find that it turns a bit slower than your current setup. If so, try a 90 in the front to get your flick rate back to what it was. You might even find that you like the profile of the sc1 90 on the front and rosso II 140 on the rear. Best bang for buck for fast paces on a 250 imho.

I do probably need to get my suspension actually setup better. I did all the suspension mods myself and just kinda based it on feel. I will get with the local suspension guy to help get my base line.

I used to go through 2 fronts to one rear when I was running street tires, not so much the case since running the alphas

Its hard to imagine running a smaller tire with the current issue, but maybe my setup is way off currently.

[csmith12]

I figgered as much, your story sounds alot like mine and worded the same as I said it in my head.

The tire size is kinda irrelevant in the grand scheme of things, it's the tire's profile and contact patch at lean angle that matters. Smaller tire(s) does NOT equal less rubber on the tarmac.

[Dsheumaker]

Originally Posted by csmith12

I figgered as much, your story sounds alot like mine and worded the same as I said it in my head.

The tire size is kinda irrelevant in the grand scheme of things, it's the tire's profile and contact patch at lean angle that matters. Smaller tire(s) does NOT equal less rubber on the tarmac.

I'll get some measurements done and hit you up, the more we talk the more it seems Like our styles are similar haha

[csmith12]

Honestly, from your videos you have posted... I have little doubts.

[Dsheumaker]

I did finally touch my elbow this weekend at NcBike. It felt so great!

[AwDang]

Originally Posted by Dsheumaker

I did finally touch my elbow this weekend at NcBike. It felt so great!

Dude...if you're that far over, it must be working!

[Dsheumaker]

Originally Posted by AwDang

Dude...if you're that far over, it must be working!

Always wanting more....

[Dsheumaker]

So when i got home yesterday i went to have a closer look at my tires and realized that i wasnt as close to the edge of them as i thought i was when i was at the track. Ill give a full explanation on what made me look at it while i was there.

So riding with TPM they have a ninja race series where its mainly the mostly stock 300s and modded 250s. I was trying to see where i fit in in the group while out on the Advanced group. There were about 5 of us having a make shift race. The 300s can pull me down the straight pretty bad but i can hang with them in other areas for the most part. I was chasing one of the 300s through the long turn 5 not wanting him to pull away so that i could stay close to get a draft down the straight on him again. In trying to hang with him i got tense on my bars i believe and then that's when the front started getting choppy feeling and pushing but i relaxed and kept pushing on. When i got back in the pits is when i glanced at my front tire and i thought that i had ran out of tire. Guess i just need to work on staying relaxed more than anything.

Attached are both sides of my front tire

[Sirref]

That looks about where I was on the front when I touched elbow in 5. Some of the motoamerica kids are getting even lower than that too so you're good.

Have you run into any clearance issues? I cannot for the life of me prevent my pegs from dragging

[Dsheumaker]

Chasing Frank through five is the first time that i touched my toe with my current setup. I think having my rear raised a tad helps out a ton. Before my current setup i would drag my pegs and the stock exhaust everywhere,

[Sirref]

Yeah, on my current setup I am dragging peg and foot everywhere and exhaust on the curbing

currently looking into other options or setup improvements

[csmith12]

Thanks for the pics, not sure your issue were front tire usage as yours looks like mine... nearly identical in fact.

However, like you did... perk up and notice when your bike gives you negative feedback. Something is going on and it's your job to figure it out, the bike simply obeys or falls. Could have been anything really, air temps, surface temps, air pressures in the tire, tight on the bars, too much weight in the front... (my money is here) the list goes on and on. Charging the corner has caused soooooooo many of my pushes and slides trying to carry corner speed to keep up with faster bikes. Perhaps that is what happened to you.

Gratz on breaking through personal bests though!

[jBazz]

Originally Posted by Sirref

Yeah, on my current setup I am dragging peg and foot everywhere and exhaust on the curbing

currently looking into other options or setup improvements

Did you check your sag #'s and what did you do to counter the lowering affect of the GSXR shock ? I think you could be running a bit low. Just throwing ideas out there. I used new links to bring the bike back up.

Im leaning towards getting a Penske for next season(something with the correct length and high adjustment built in)

[Sirref]

Sag is correct, was set at the start of the season. I have the rear raisef slightly but am worried that if I raise it more (above stock height) it will ruin the geometry of the bike. I'm considering going with a penske for next year. If I want to keep up with the big boys I feel I need to be on at least the same equipment as them

Gonna replace the exhaust too to help prevent that from dragging on the curbing

[tgold]

Originally Posted by Sirref

Sag is correct, was set at the start of the season. I have the rear raisef slightly but am worried that if I raise it more (above stock height) it will ruin the geometry of the bike. I'm considering going with a penske for next year. If I want to keep up with the big boys I feel I need to be on at least the same equipment as them

Gonna replace the exhaust too to help prevent that from dragging on the curbing

You can raise the front and the rear to minmize the effect on changing the steering geometry. Not that raising both ends wouldn't have any effect, but at least it wouldn't change steering head angle.

But you may find that you like the handling better by only raising the rear more. The way to find that out is to go to a track day, ride the bike as it is for one session, make the rear ride height change to see what effect it has and if you like it, then you're done. If you don't like it, then you raise the front of the bike an equal amount and go check it out again. If you like it then you're done. If not, you can always go back to your original setup. The key is to only make one change at a time so you more fully understand the effect that it has.

[Sirref]

^That is currently my plan for this weekend

[howlinhoss]

Originally Posted by Sirref

Yeah, on my current setup I am dragging peg and foot everywhere and exhaust on the curbing

currently looking into other options or setup improvements

Would getting yoshimura rearset brackets plus rear sets help with dragging peg and foot?

[Sirref]

Originally Posted by howlinhoss

Would getting yoshimura rearset brackets plus rear sets help with dragging peg and foot?

Yes, but that opens you up to my current issue. The belly pan and exhaust (exhaust on curbing) drag instead. Granted that is at slightly more lean angle so the efforts worked to some extent

[Dsheumaker]

Thanks to @howlinhoss for the video up load. Here is one of the fun sessions at NCBike a few weekends ago. I come around the 6 min marka nd then again for 2 laps starting around 9 mins in.

https://www.youtube.com/watch?v=ZJJ1fZaqQr8

Link to original page on YouTube.

[Alex]

[shift957]

David, something you may not have considered but is definitely a factor: you are on a 250 fighting to keep up with 300's. If you can't beat 'em on the throttle, you get better on the brakes and cornering to do what you can. When I raced my 250 against the 300's last year, I had BT016's on and ate more front tire than rear. Being down on power, I had to out brake (at VIR for example) others in T1, T7 and at the top of the roller coaster. I also had to carry more speed and pass 300's on the outside at the bottom of the hog pen, to the point of front end chatter, only to get passed back on the straight and play the trail brake game again. It was pretty obvious in my videos there. So I have no doubt you are doing the same things whether you realize it or not.

And if you say you were putting some tension/input into the bars while riding, that will definitely accelerate it. Relax mon