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Old Dec 01, 2012, 04:18 AM
If u aint 1st your last
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Originally Posted by chktm View Post
Looks pretty good TJ. How wide are they? Could you cut them down the centre to make two?
That is a front insert you would only get one from it athe rears are wider but i don't have one here to look at, i have not had a look but i would say most 1/5 are probably the same size.
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Old Dec 01, 2012, 04:25 AM
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Originally Posted by Throttlejunkie View Post
That is a front insert you would only get one from it athe rears are wider but i don't have one here to look at, i have not had a look but i would say most 1/5 are probably the same size.
Cool ill check them out.
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Old Dec 01, 2012, 04:28 AM
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Originally Posted by Jonathan Bradbury View Post
The ''glaswegian insert'' on the M5 seems to do very well on grass with an even and smooth surface.I'll bet any Arx450 owner will concur. As Gartenzweg was speculating about hard inserts being the best way on road, so I suspect nice flat grassed ground (eg Millenium Stadium, Cardiff) would be best with a rock hard insert.

The problem of course is all the little stones, that scaled up, become huge monsters! That's where this thread belongs. Finding what works in less than Savile Row Pressed surfaces.
Yes JB i concur, the arx does work well on grass & tarmac but takes a bit more finesse on the rough dirt with no insert compared to the mm450 it seems to maintain it's traction with the soft tyre & insert set up.
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Old Dec 01, 2012, 12:21 PM
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That answer ties up with the Roadies concept of ultra hard inserts working on hard smooth ground. I suspect tread patterns that do not squirm will also benefit, although with previous experience of squirmy tyres on tarmac with the mountain bike and the M5, it could be used to an advantage allowing you to back the rear end in into corners, though I suspect that a hard as nails tyre compound/block pattern would follow MotoGP findings of improving front end stability.

The problems always occur over divots/stones etc and I believe that a slightly forgiving front tyre would be best for most ''true'' off road conditions. The pic chktm posted is a fair reflection on the types of ground we expect to cover with good grace, but scaled up, you'd be filling nappies at the rate of 1 per 50 yards if you were on say an old XL250s flat out. But I expect most race tracks are not covered by such monster rocks.

I will therefore propose that as a 'general' rule #1, Ultra hard inserts front and rear work well on smooth ground the best. The tyre choice would be down to preference and surface eg grass or the hard pack of a BMX track.

I suspect that almost any tyre tread pattern would work on a dry BMX track type surface dependent on riding style. Something I'll test in the late spring when the glorious brit weather becomes less wet as I've found a really nice one 25 miles away that the local buggy brigade sometimes use. I've found virtually no difference in performance between a new Anderson tyre and one with the knobbles ripped off on grass or hard pack mud so I would assume that a squirmy tyre would just let you back the rear end in more (a style I like, especially with having no front brake).
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Old Dec 02, 2012, 02:55 AM
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A few notes from my recolection having tested many tires...

You have to look at the relationship of the tire to the terrain. Slick tires for ashpalt, hard packed dusty tracks and a mini block tread, loose dirt 3-6mm deep top soil / more open tread with deeper pins, gravel / stock VMX tires or similar, grass / VMX tires or similar.
So basically the more loose the terrain is and the larger the particles are the more open the tread has to be. This is just basic tire to terrain relationships like choosing the right saw tooth count for the material your cutting, same thing your processing material either way.

Longer lugs compared to shorter lugs.
Longer lugs provide more compliance. That means more give and side to side sway in the contact patch under load. They also brush away debris and penetrate through loose top soil down to harder soil. When the pattern is more open, fewer lug count, the tire will handle larger particles. Combined with longer lugs and a low count the tire will be very open like a motocross tire in full scale. 

Shorter lugs have less compliance, harder feel, break loose more abruptly. Again for hard packed low dust surfaces this is a better option. Usually the lug count is higher as well. 
On dry dusty surfaces like hard packed buggy tracks ( because they require nearly zero maintenance) you want a "fuzzy" block type tire typically used by 1/8 scale buggies. This tread pattern is able to get through the dust layer and hook up on the sand paper like surface below. 

You can imagine whats in between these conditions when it comes to other tires and terrain. But here is where it gets interesting. On a polished concrete surface in a typical warehouse the longer MXR lugs work great... Why? Tire Compliance

This says nothing about rubber compound, insert firmness, sidewall design, carcass thickness, lean angle, lugs with a base radius or not or a number of other factors in tire design and set up.

Insert firmness is very important on the VMX, the bike is sensitive to this. You have to balance it with suspension set up, its all related. You can play around with different inserts front and rear but generally you want a softer rear insert because it is the driving tire and it must find grip at all times when accelerating and braking. 
If the inserts are too firm the tires will ricochet off of objects rather than roll over them comply with the shape and deform. This directly ties into steering damper set up and suspension dampening. The more firm the insert is the softer the suspension dampening has to be because the rebound speeds increase with harder inserts. 

Best advice is to take a look at your local 1/8 track and see what the fast guys are running on their buggies and truggies. Copy that in a pair of tires you make for the VMX and try it with different inserts and suspension tuning. This will get you as close as possible for starters and from there you can make other changes and adjustments to the bike or make a new set of tires. 

Also! Dont think of the VMX like a buggy... ITS a BIKE! 
Half as many tires, 25% of the contact patch a buggy has but similar in weight. 
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Old Dec 02, 2012, 12:29 PM
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Great info ChrisN, glad to see you around.
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Old Dec 02, 2012, 11:05 PM
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Quote:
Originally Posted by Chris Nicastro View Post
A few notes from my recolection having tested many tires...

You have to look at the relationship of the tire to the terrain. Slick tires for ashpalt, hard packed dusty tracks and a mini block tread, loose dirt 3-6mm deep top soil / more open tread with deeper pins, gravel / stock VMX tires or similar, grass / VMX tires or similar.
So basically the more loose the terrain is and the larger the particles are the more open the tread has to be. This is just basic tire to terrain relationships like choosing the right saw tooth count for the material your cutting, same thing your processing material either way.

Longer lugs compared to shorter lugs.
Longer lugs provide more compliance. That means more give and side to side sway in the contact patch under load. They also brush away debris and penetrate through loose top soil down to harder soil. When the pattern is more open, fewer lug count, the tire will handle larger particles. Combined with longer lugs and a low count the tire will be very open like a motocross tire in full scale. 

Shorter lugs have less compliance, harder feel, break loose more abruptly. Again for hard packed low dust surfaces this is a better option. Usually the lug count is higher as well. 
On dry dusty surfaces like hard packed buggy tracks ( because they require nearly zero maintenance) you want a "fuzzy" block type tire typically used by 1/8 scale buggies. This tread pattern is able to get through the dust layer and hook up on the sand paper like surface below. 

You can imagine whats in between these conditions when it comes to other tires and terrain. But here is where it gets interesting. On a polished concrete surface in a typical warehouse the longer MXR lugs work great... Why? Tire Compliance

This says nothing about rubber compound, insert firmness, sidewall design, carcass thickness, lean angle, lugs with a base radius or not or a number of other factors in tire design and set up.

Insert firmness is very important on the VMX, the bike is sensitive to this. You have to balance it with suspension set up, its all related. You can play around with different inserts front and rear but generally you want a softer rear insert because it is the driving tire and it must find grip at all times when accelerating and braking. 
If the inserts are too firm the tires will ricochet off of objects rather than roll over them comply with the shape and deform. This directly ties into steering damper set up and suspension dampening. The more firm the insert is the softer the suspension dampening has to be because the rebound speeds increase with harder inserts. 

Best advice is to take a look at your local 1/8 track and see what the fast guys are running on their buggies and truggies. Copy that in a pair of tires you make for the VMX and try it with different inserts and suspension tuning. This will get you as close as possible for starters and from there you can make other changes and adjustments to the bike or make a new set of tires. 

Also! Dont think of the VMX like a buggy... ITS a BIKE! 
Half as many tires, 25% of the contact patch a buggy has but similar in weight. 
Hi Chris, I agree with most of the above with the exception of using a fuzzy type tyre on dusty hard packed clay on these bikes. Sure they will work great but because of the amount of weight and drive being put through one tyre, I think a tread pattern more like a real bikes hard packed tyre ( or even speedway or trials tyre ) with lower knobs and more coverage but the knobs are a lot bigger and wider than a fuzzy type tyre. Because of the weight and gyro the traction from this sort of tread is good. Also even less tread movement. And best of all you get more than 5 minutes of running before the tread is fried. The fuzzy type tyre was originally designed to get traction for a much lighter vehicle ( 1/10 electric, I know they now make them for 1/8 buggies but they are more of a qualifying tyre not a finals tyre ) and also for quite short race duration. 25% contact patch means a lot more wear through one tyre as lots of buggies are 4WD. All bikes respond to tyre pressure changes similar to insert firmness. You don't want too hard or too soft. Just as with a firmer insert you may need a quicker shock action, if you use a softer insert you can get away with using a much firmer and slower shock action. This is the way I prefer to set up my bike. The bike still handles the rocks and sharp bumps ok but excels on the higher speed stability through bumps and seems better on jump landings and bad jump faces.
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Old Dec 03, 2012, 04:55 AM
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This is a newest version of a fuzzy tyre to suit a 1/8th buggy. There is a little more depth to the tread to increase the life but also doesn't squirm much as the knobs are supported. Not sure how much extra life?
http://www.rcgroups.com/forums/newat...anageattach&p=
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Old Dec 03, 2012, 10:32 PM
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Originally Posted by chktm View Post
Hi Chris, I agree with most of the above with the exception of using a fuzzy type tyre on dusty hard packed clay on these bikes. Sure they will work great but because of the amount of weight and drive being put through one tyre, I think a tread pattern more like a real bikes hard packed tyre ( or even speedway or trials tyre ) with lower knobs and more coverage but the knobs are a lot bigger and wider than a fuzzy type tyre. Because of the weight and gyro the traction from this sort of tread is good. Also even less tread movement. And best of all you get more than 5 minutes of running before the tread is fried. The fuzzy type tyre was originally designed to get traction for a much lighter vehicle ( 1/10 electric, I know they now make them for 1/8 buggies but they are more of a qualifying tyre not a finals tyre ) and also for quite short race duration. 25% contact patch means a lot more wear through one tyre as lots of buggies are 4WD. All bikes respond to tyre pressure changes similar to insert firmness. You don't want too hard or too soft. Just as with a firmer insert you may need a quicker shock action, if you use a softer insert you can get away with using a much firmer and slower shock action. This is the way I prefer to set up my bike. The bike still handles the rocks and sharp bumps ok but excels on the higher speed stability through bumps and seems better on jump landings and bad jump faces.
I understand what your saying and maybe its counter intuitive but I tested this and it worked great on hard packed surfaces. That is why the race track tire I designed is a hybrid of a fuzzy tire but for a motorcycle.
Just make a set and see for yourself.

What a fuzzy tire does really well is to allow the dust to pass through the lug gaps. They have a lot of lugs so there are a lot of driving lug faces and edges gripping through the dust onto the hard pack. Hard pack is like sandpaper there is grip but you must get passed the dust. The small lugs and dense pattern get through the dust by brushing it away and then hitting the surface underneath.

I studied super motor tires and speedway tires as you mentioned for inspiration and comparison. What works at our scale is more like a Proline Hole Shot, Blockade, and Tazer. Center rectangle lugs are called Drive lugs and bikes benefit from this.
I tried a truggy Caliber tire set and this was too soft and mushy. The lugs have too much squirm under load so the bike gets into long slides and vague feedback.
The way I made the tires specific to bike applications was to increase the side lug stiffness for a couple reasons. When you start from a dead stop on the guide wires you can easily blow out all the side lugs. When the bike is fully feaned over in a corner you need lugs that can handle the slide and power loads and not deform excessively.
I went through a lot of designs and tests to prove this out. There is a lot more work to be done in this field and unfortunately each mold costs about $10K. Thats why I say make some tires cheap and try them out and the foams.
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Old Dec 03, 2012, 10:43 PM
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Originally Posted by chktm View Post
This is a newest version of a fuzzy tyre to suit a 1/8th buggy. There is a little more depth to the tread to increase the life but also doesn't squirm much as the knobs are supported. Not sure how much extra life?
http://www.rcgroups.com/forums/newat...anageattach&p=
The PL Caliber is similar. This kind of lug adds height to the tire profile but these lugs squirm too much under load. The feedback is vague and the bike drifts. Its like a two stage feel; first it turns in and then slides as the suspension loads up then you have to counter quickly and power on to counter steer. It can oversteer and catch too, not a fan of these stepped pin tires for bikes.
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Old Dec 04, 2012, 02:46 AM
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The PL Caliber is similar. This kind of lug adds height to the tire profile but these lugs squirm too much under load. The feedback is vague and the bike drifts. Its like a two stage feel; first it turns in and then slides as the suspension loads up then you have to counter quickly and power on to counter steer. It can oversteer and catch too, not a fan of these stepped pin tires for bikes.
No I don't think I would be either. I can understand what you mean. I would have thought a tyre with a little more rubber than a fuzzy even, ( say a fuzzy tread but just more again, still gaps but not much )more like a real speedway bikes tyre would work good as I find the std tyres work better the more wear they have. Seriously to the point where they are bald and still pulling great wheelies cutting through dust and completely in control. Also no squirm once they are worn. Personally I can't be bothered making up a tyre as I can fry the std ones in a day so can't see the work being worth it for me. The inserts I make are a different story lasting for maybe 4 or 5 tyres. I find tuning the std tyres with inserts works great also. If i could buy the tyres i would, but only use them for track work. I think you did a great job designing the tyre that comes with the bike as it really works well on a variety of surfaces and keeps me happy all the way till bald. Here's a pic ha ha.
http://www.rcgroups.com/forums/newat...anageattach&p=
Getting my money's worth. This is why I think a tyre more like the Proline Knuckles would work really well. I guess I might have to do some testing eh. Hope for a rainy day. TJ where's that rain you sent lol. afterthought the tyre could be very similar to the std one with twice the knobs and slightly lower profile.
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Old Dec 04, 2012, 02:56 AM
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Lol, dont chuck that tire is the side wall and are OK, thats your test tire carcass!
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Old Dec 04, 2012, 03:10 AM
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Lol, dont chuck that tire is the side wall and are OK, thats your test tire carcass!
Ha ha yea I thought I would keep it for a rainy day lol.
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Old Dec 04, 2012, 10:52 AM
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reposting info from vmx discussion

10k for mold, holly molly!

Im going to repost some stuff from the vmx discussion here because its relevant and for reference. I doubt a 1/8 buggy tire will wrap over an old vmx tire carcass, instead look for truggy tires. The picture below is of a Proline Revolver VTR m2 medium compound truggy tire. I can find them in pairs without inserts cheap for about $17 at Towerhobbies. Ive seen AMainHobbies.com sometimes sells individual truggy tires dirt cheap too.

Hope you dont mind I quote you ChrisN from the vmx discussion responding to my picture I posted...
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Originally Posted by Chris Nicastro View Post
I'll help you out.
I've used M3 and other super soft rubber tires and that is the way to go. The grip on track is great. Ive run several packs on this set up and they hold up for quite a bit of abuse. Just do not run it on pavement.
Use a PL truggy tire and use rubber cement but first prepare the two with a Dremel sanding drum to take off the ribs and smooth out the lugs on the MX tire.

You will also need to adjust the steering damper due to the increased front grip. I used up to 100wt oil in the damper to get faster steering from lock to lock. The issue is keeping the front wheel down in order to steer so throttle use and set up become the next subject.

It's awesome so I'm looking forward to your results, I liked what I tried on track.
Chris
Once I get my bike sorted out I will get back to testing this:
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Old Dec 04, 2012, 01:06 PM
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I'm glad I started this thread, it seems long overdue.

I do regret no real participation from Jena67 or Gartenzwerg though...

Mind you, I can't test things on the M5 to further input here either. The track goes from 'The Glastonbury Festival' to 'The Arctic' to 'The Monsoon Season' within days.
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