David checks out this pair of Goodyear Newton tyres, the latest MTB rubber from Goodyear.
Despite starting out making bicycle tyres at the end of the 19th Century, from the mid-seventies, Goodyear took a 40 year break from bike tyres. That was, until they signed a deal with Kent International, who own Rubber Kinetics LLC (Rk).
After two years of development, Rk has some high end mountain bike rubber in the form of these Newton tyres, of which I’ve been testing a Newton ST EN Premium in 27.5in and 29in, and a 27.5in Newton EN Premium, which is slightly faster rolling with a different tread pattern.
The naming on these gets slightly confusing, as they’re basically different tyres, with very similar names, that use a lot of two letter acronyms. The “EN” in EN Premium refers to the casing, which is the most robust they offer to go with these tread patterns. “ST” is a mystery (Staggered tread? Super tyre? Silly title?), but of the pair, it designates the front tyre.
Up front, the Newton ST has staggered centre knobs to give better cornering performance. They’re not too tall, ramped to reduce rolling resistance, and fairly widely spaced. The rear tyre Newton (non-ST) centre knobs are aligned laterally into rows, disposing it less to cornering than the ST one, but maximising braking traction by presenting plenty of edges at a right angle to the bike.
Both have the same side knobs.
On first poke, these had a kind of waxy surface texture that felt like it might be mould release compound. More on this later.
These are really not easy tyres to fit and, while that was frustrating, it does also seem to have some benefits when it comes to bead and air retention.
The 29in tyre had been fitted and ridden by Ross for a few rides before I got hold of it, and went on and up quite easily as a result. The brand spankers 27.5in ones though, sheesh! Things I did while trying to get the first of these on:
- Started with a carbon wheel.
- Resorted to zip ties just to stop the tyre ejecting itself from the rim
- Honest to god double-checked it wasn’t a 26in tyre.
- Pulled it back off, syringed the sealant out, and added a tube to try and stretch it out.
- Nearly cried.
- Gave up on that wheel.
- Swapped to a wheel with a Stan’s Flow EX.
- Took an hour off for my poor thumbs.
- Straightened or snapped most of my tyre levers.
- Nearly cried getting the second bead in.
Weirdly, adding copious soapy water to the beads seemed to hinder rather than help. I was at the point of giving up when, on the off chance it could make a difference, I dried the tyres out and tried inflating with no soapy water and no sealant. Pop, pop, pop, pop. It felt like a miracle. A weird miracle.
These tyres aren’t UST rated, but seem to be most of the way there. Impressively, they all mounted and stayed up for several days without any sealant. When they eventually went down, I saw the beads were so tight that they’d dismounted and migrated back down into the rim well.
I decided to inflate them like this for a few days more, to see if they’d stretch a bit. Answer: Yes, a little, making them easier to pop on and off wheels.
Add rim inserts and 25mm internal width rims to double the fun. With all of that in the equation, on new tyres I had to use zip ties to stop beads popping back out. Ouch. Second mount was much easier, but still required levers. I don’t think these will ever be a baggy fit.
They’re fairly heavy tyres too, with the Newton 27.5in weighing in at 1074g and the Newton ST at 1065g. While it is a folding tyre, the beads and sidewalls are so reinforced with rubber that it feels like a downhill tyre.
On a selection of Stans and Mavic 25mm internal rims, measuring corner to corner on the widest side knobs, they came up at 2.3in rather than 2.4in.
On The Trail
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|Product:||Newton and Newton ST|
|Tested:||by David Hayward for Two months|