Has anyone tried @Tony_Stark Radium sr125’s on an indoor surface?
3 Likes
Not yet, but one of our guys have just received his set. AND were at the indoor track next weekend 
5 Likes
Would you use larger tyres if you could lower the ride height to compensate?
Partly because of the double stack enclosure and partly the excessive drop brackets I can scrape with 8”s. And with the negative lateral g pushback thing I think it sounds ideal. I can also gear down a good bit too.
I know it’s a tad less stiff and responsive, and less efficient too but there should be a good bit more grip and tread in the tyre too.
1 Like
I’m no one, but I would! Especially after seeing what @Dinnye is doing with go kart tires. All I want to do is copy! with a little of my own flair
1 Like
The kart tires are still completely untested - I am waiting for the aluminium wheel hubs to run them.
If everything goes according to plan I might be able to be do the first tests on them at esk8con, however without the further lowered chassis yet I think they will feel pretty tall. I’ll also have a set of BRPs as backup.
The new chassis is probably getting finished in May - assuming all goes well, I’m hoping to be running it at the race in Prague mid May.
Stooge seems to have good experience going up in tire size and lowering the chassis on the WTF - I’m taking that a step further. But it’s gonna be a couple months until there’s a confirmation if I made the right call or just wasted a bunch of money.
3 Likes
Having said what I did in the previous post - there’s a reason why I am doing adjustable ride height chassis. The surface you are racing on has a large effect on tire choice. 6-6.5" works indoor almost always and there’s a few tires that really shine. And I don’t want to rule out the option to have the known tire options to fall back onto if I find out that some surfaces don’t play nice with new previously untested tires.
If you go up in width you absolutely need to go down in duro, which isn’t always possible. The reason I went all the way up to kart size 10x4.5" from the approximately 8.5x3.3" (9x3.5) of my previous setup was to go down in duro.
Unless you are looking at a size of tire that’s used in competitive racing, you won’t be able to compensate with duro and will ultimately end up with tires that you can’t get up to operating temperature well and therefore won’t grip like they should.
The only reason why I am fairly confident the kart tire experiment will work, is that they feel soooo much softer than any other esk8 tire that’s out there.
Another question with the kart tire experiment is how far can the standing platform be below the axle before it feels like too much - that one only time will tell.
4 Likes
I can’t wait to hear! It’s super neat and looks incredible!
3 Likes
Technically this doesn’t necessarily have to be the case, there’s tires out there that even though they might have a tall sidewall, it’s so stiff that it still feels responsive. My CST C190 9x3.5 set for instance really feels nice and responsive on the grip limit - but it’s response is damped by a tiny bit compared to the linnpowers. In my opinion it feels really nice - the harsh transition that the linnpowers have is less manageable, but the cst still react very quickly, just a tiny bit slower which actually makes a mistake easier to recover from. You need to build up skill to be able to really tame linnpowers on the edge.
With the kart tire experiment the ones I have right now feel more like a medium sidewall - I probably want something a little more aggressive for high bite surfaces. If I end up liking this sidewall the way forward is MG green compound, if I need a stiffer sidewall the way forward is LeCont LPM.
There’s one more thing to consider regarding sidewall stiffness - how much the tires bite the track. High bite surfaces like asphalt tend to work best on aggressive, stiff sidewalls, whereas on low bite surfaces like indoor kart tracks stiff sidewalls feel harder to tame on the edge, therefore a medium sidewall might actually be preferable to perform more consistently.
4 Likes
Thank you, that’s helpful. I probably wouldn’t go larger than 8” nova or 200x75.
Also would you like some big spur gears for the go kart tyres? I have the files for up to 127 tooth mod 1.5. When I’m getting more stuff lasercut I’ll put some in whatever size you want, you can decide if you want them after getting pics, I would only charge shipping and refund it if they fit like crap or break. MBS pattern right?
(I’ll throw in some Apex anti-sink plates for Raceboi)
2 Likes
I haven’t tried 8" novas, but the compound in them should be good. My worry would be the tall sidewall, which probably feels more like a soft-medium sidewall. I think it’d be a forgiving and fun setup to practice on, while delivering decent performance, but once you have a lot of practice you’d probably feel like their response is slow when driving them on the edge. Indoor low bit tracks you should be mostly fine I think. Although the 7" sidewall would probably be somewhere around the sweetspot for slick indoor I think.
There’s 8x3 slicks but you need a 4" diameter rim for them (for example MBS pro ii xl) happy to send you files to widen those hubs, they work decently. These should feel nice outdoor (but probably not as grippy as the best race tires) and probably too hard to heat up on most indoor surfaces. I’d recommend experimenting with CST C190 first just because I had good experience on it’s 9" equivalent. There might be other options with softer compounds that might have a slight edge. The 8x3 slicks I tried had stiff sidewalls, so most of them should be nice and responsive.
Regarding the gears I appreciate the offer! I have to think it through. I was planning 78T until now.
I could definitely use some help for lasercutting the frame though if you are up for that? Happy to pay you for that of course. I’ll send a DM later.
3 Likes
Thanks again, I’m not doing proper racing or pushing as hard and going through as many tires as you guys so it helps to get the info! Tbh the choice would be influenced by day to day riding a bit too where the tyres wouldn’t warm much anyway and more contact area helps. I overdid the brackets so I’m on 20mm of risers and low so larger tyres would help axle/deck height.
Feel free to send a dm, I’m in Ireland and got parts from Fractory in the Uk in the past so it might not make sense to send bigger parts (although it was super cheap) but I’m sure I can help at least a little.
I’m not sure when I would get more stuff lasercut and in bulk it wouldn’t put a dent in the cost so lmk what tooth count you would want, you won’t be under obligation to buy or use it or anything don’t worry. There’s a decent chance they will be just of too low quality so I couldn’t make promises or accept payment.
Idk if this is the best place to ask, but it seems like a reasonable one.
Does anyone know if they actually use a different compound on the C190 “kart tires” and the C190 mower tires? I’m having a hard time finding places in the US to buy the 8" slicks at all, but the main place I found them was selling them as mower tires. Also, unfortunately, they’re back-ordered, and they don’t have an ETA. It does seem on their site the cart tires have “Challenger” in the name, and the mower tires don’t, but I’m having trouble finding much information.
The lawn tires only being $12.25 makes them pretty damn cheap tires if they’re any good.
1 Like
Also, just as an informational point, these Kenda lawn tires claim to have a durometer rating of 63:
which I think is reasonable. I’m used to durometer ratings also having a letter, though. Anyway, I think maybe these could work or even are the same as the kart tires, but I’m not sure.
1 Like
I would also be super interested to hear about their performance.
These are the ones I’ve used.
Here’s a source for the kendas in supposedly the 63A compound.
I think @Flyboy ordered both to compare them?
Anyways my experience on the CST 9x3.5 is forget them indoors, they are as bad as on ice pretty much. But pretty good outdoors. Hard to heat up, needs ambient temp and a certain abrasiveness of the surface to work optimally.
I could T-race 13.43 (?) I think on them. Since swapping to the Linnpowers I went down to 12.82 - part of this difference is just me getting better, but they do grip slightly worse in my usual practice spot. Not by much though when ambient temp is high. As soon as ambient temp drops they suffer more.
1 Like
Unfortunately he is still in the process of making adapters for the SRB hubs to fit the wheels. Will keep you updated once we dinally get to try them
4 Likes
Id be open to trying it on the 2WD Brady deck once i get it up and running, but i cant lower the ride height of the V5 to justify 8in tyres unfortunately
3 Likes
Yep, but I only did an inclined plane test. “Lab” results, not real world riding, indicate 20% more static friction than the CSTs. I’m pretty far off from having a board to ride them on.
2 Likes
