Bontrager FR4 experience? FR4/FR3 combo?
Any comments/reviews for the Bontrager FR4? It looks like an aggressive high volume tire, average weight, but may roll well?
Did a search, just one review and not much detail. I have been thinking about running one of these on the front with an FR3 on the back.
They call me Cakey.
I've been looking for reviews as well though as a back tire. There's a detailed one man's opinion that just showed up in the mtbr FR4 reviews that I found helpful.
Luv n take care of yr bike. It will b more faithful than any woman or dog. Of course u cant blame a fart on yr bike. -Earl
I bought the set-up, and I am very happy. I wanted to review the FR4 but couldn't find it as an option in the review section. The FR3 is there, I'll have to give my $0.02.
Overall this is my opinion:
Setup: Moderate to install. I set them up tubless. Getting the last bit of final bead to get on the rim took some serious hand strength and manipulation. Not overly difficult, but it reminded me of putting on some DH or road tires. The FR3 had a nice ping when aired up, the FR4 was dead silent when I put it on, so I didn't think it seated correctly, but the bead looked like it was in the right position. I used 2 scoops of stans, aired them up to 50 psi for the night and no leaks the next morning. Aired them down to 25 FR, 27RR and was good to go.
Weight: They are not light, but as all mountain/freeride tires go they are a respectable ~850g for the FR4 and ~800g for the FR3. Bontragers site specs slightly different weights, this is what I measured. Add some stans to that mass and you're right at a normal UST reinforced sidewall aggresive tread tire.
Rolling Resistance: Great. Regardless of the mass these tires have they roll very well and feel fast. I had read the FR3 rolled well, and it does. I have it at 27psi. The center rib aids in that feel and it is a consistent feeling tire in most conditions. I haven't ridden them in the mud yet, however. The FR4 rolled well too, surprisingly. I have it at 25psi and although it has some very aggressive knobs and is a large volume tire it also rolls fast and feels nimble.
Traction. The FR4 has amazing front end traction. Braking and Steering feel improved over my previous High Rollers. I have more confidence going into turns and have a better sense of consistent feeling and control with this tire. The FR3 holds it's line, brakes well and accelerates reasonably. As a combo these tires seem to work well together and can be leaned over with the same feeling received from FR and RR.
Durability: I've only had them on two rides, so I can't comment on that yet.