GRP 1/8 Scale On-Road Tire PSA

[Diem Turner]

Just a heads up to anyone who never thought to confirm their stated dimensions...

They've always been listed everywhere I've seen them as having a 98mm diameter (3.858"), this includes any of their own tech specs. This goes for both the old style 14 spoke wheels as well as the new(er) 20 spoke wheels. I always figured "why would they misrepresent something so basic that any moron can confirm (or not)?". What is it they always say? Measure twice, cut once? Don't ask me how that applies here...because it doesn't. But my calipers don't lie. They actually clock in right around 96.5mm (3.8"). I've checked two sets of four GTK 20 spoke in compounds 5 and 7 respectively and all eight tell the same story. So if you've ever found your calculations a bit off with them, that's worth about 2.5mph on 3S around the 110mph mark. Scale as needed.

I'm certain that I'm not the first to notice this (came up short and a couple of years late) and it's probably been mentioned somewhere but it definitely passed me by and in case there are other trusting and naïve rubes out there that just believe what it says on the tin...consider yourself told. Of course ballooning will recoup the difference at speed but, if you're calculating tire ballooning as I was...what the one hand giveth, the other taketh away.

Happy motoring!

 

[Moirae]

wow i remember reading that the newer grps were 99mm.

 

[fozzy71]

GRP GTV02-S7 1:8 GT T02 SLICK VELOCITY S7 MediumHard Tires Closed Black Wheel (2)
Ordered on July 9, 2019 (1 item)

40mm/96mm, after a few packs.......

 

[Diem Turner]

wow i remember reading that the newer grps were 99mm.

FWIW, I'm not telling you not to believe what you're reading. I'm only telling you that it's wrong.

GRP GTV02-S7 1:8 GT T02 SLICK VELOCITY S7 MediumHard Tires Closed Black Wheel (2)

40mm/96mm, after a few packs

I'm at 96.5mm on a set of GRP 1:8 GT T03 REVO XM7 almost unused. Maybe half a pack, no burn out or other such use that would accelerate wear. And 96mm on a slightly used set of GRP GTK03-XM5. I'm certain neither of these sets ever had a 98mm diameter.

 

[fozzy71]

I'm certain neither of these sets ever had a 98mm diameter.

What is this thread about? 2 or 3 mm?

p.s. I said 96mm, not 98.......

 

[Diem Turner]

What is this thread about? 2 or 3 mm?

p.s. I said 96mm, not 98.......

Yes. That's exactly what this thread is about. As I said, that's 2.5mph speed delta at 110mph. I find it incomprehensible that a company that makes as many wheels/tires as GRP isn't familiar with the dimensions of their own product. Thank Christ they don't make machined products.

And yes, I know you said 96mm. These contact lenses work ya know.

 

[deanwrx]

Yep. I have some 1/8 GRP from 2 yrs ago. They have minimal wear and come in at 95.2mm lol

 

[fozzy71]

Yeah, even if a site does mention a mm diameter it might not even match up with what my digital calipers say when I check them. ¯\_(ツ)_/¯

 

[deanwrx]

Yep. I have Jetko 1/8 SGT 3.8 EX Super Sonic Belted tires. MFG states the diameter is 130.2mm. I measured them and they are closer to 125-126mm. I emailed Jetko and they confirmed the tires are closer to 125mm and the listed diameter is an error. But I have yet to see any updates on the true diameter size on any site that sells them. These guys just don't care.