All you need to know about tire pressure

Screen_Shot_2016-07-05_at_11.30.31_AM_grande

From here.

Advertisements

Michelin Wild Race’r Review – 29 x 2.25

I liked this tire in the 26″ circumferenceway. I do not like it in the 29″ size – during dry conditions.

For some reason the 29″ size was extremely difficult to mount and remove from my WTB i19 rims. I had to use a tire jack and/or a special tire lever to complete the install. So that kind of set a negative tone going into using the tire.

Overall the tire rolls fine and is well made. Runs true laterally and radially and has consistent bead, knobs and sidewall thickness. Seems like it’s about average as far as suppleness goes – my normal PSI set it to a normal amount of sag and the sidewalls seemed well supported during hard cornering and off-chamber root/rock strikes.

However I think the tread design is just too aggressive in the 29er size when riding dry trails.

Well, actually, it’s the wrong kind of aggressive. It has well-spaced diamond knobs in the center that are mid-height and grip well without impeding rolling resistance. But the outside knobs are significantly more aggressive and do not interact well as the bike leans into a turn. The tires, especially in the front, tend to turn in like this.

No lean – normal rolling ok traction

Mid lean – less traction normal rolling

Hard lean – EXTREME TRACTION

As the center knobs hand off to the side knobs the tire bites hard and causes significant oversteer. It’s hard to track and hard to adjust to since the increased traction pulls your front wheel into the turn but it’s dependent on the dirt surface/composure. I can sort of account of it by counter-steering and leaning the bike but it’s harder to do this when I’m tired or have a high mental load like during the start of a race or very fast technical sections.

For some reason (maybe I’m crazy?) this oversteer is less pronounced in the 26″ size? I never had an issue and liked the way the 26″ tire handled but for some reason the 29″ just doesn’t perform as well during high speed and aggressive riding on dry singletrack.

Now, I think the tire is probably great in more muddy conditions when some of the trail is dry and some is muddy and it’s pretty good for gravel with mixed pavement too. I’ve replaced it with a tire that has more consist tread from center to sidewall but do plan to bring it back once the gravel season if over and just use it as a regular every day tire.

Kenda Slant Six 29×2.3 Review

http://bicycle.kendatire.com/en-us/find-a-tire/bicycle/cross-country-marathon/slant-six-pro/

2017-03-22_9-20-54

These are the stock tires on the 2016 Raleigh Tekoa Comp I recently purchased. They are without a doubt the roundest tires I have ever seen. I’m not sure if this is due to the wide 30mm rims or just the tire profile but wow look at that curve. The roundness allows the contact patch to stay a consistent size and profile as the bike is leaned over. On a less round tire, as you lean over the contact patch changes size and often gets narrower and longer. This can lead to inconsistent feel as traction can change depending on lean angle and often goes from a lot->a little->a lot and this change in traction can cause over-steer or under-steer.

Over Under Steer

So, very round and very wide.

Left to right; Continental Race King, Michelin Wild Race’r and Kenda Slant Six.
How do they ride?

They roll over everything. The tires are tall, 58mm/2.28, so there is a lot of float and rollover. I’m still fine tuning the pressure but otherwise they ride very well. Pedaling feels kind of mucky but it appears to just be a feeling as the speed is not affected. Kind of like riding a cushy road tire, you feel slower but you’re actually going as fast or faster.


Being so tall and wide there is some potential for self-steer and over-steer during turning so lower pressures may not work very well with these tires.

Traction seems very good, the tire compound seems really grippy. I’m not sure if that is just because they’re new or if it’s the compound itself but I had no issues in the dry during hard cornering or front-bias downhill braking. I ran a tough descent in my fastest time ever, cutting 23 seconds off a segment where my previous time was 1:54.

Overall I’m happy with them and plan to use them for the races I have for the rest of the year.

Michelin Wild Race’r Review – 26 x 2.25

I got these tires because they were reasonably cheap ($24.99 from Wiggle), have a mildly aggressive tread that looks like it will roll well on pavement and were reasonably lightweight. Basically I plan to run these on my gravel hardtail for the 2-3 races I’m participating in this year. Last year I rode Forte Tsali 2.3s which were ok but seemed slow on pavement and smooth gravel. So these seemed like they would be a little faster option.

Here’s Michelin’s webpage for them: http://bike.michelinman.com/tires/michelin-wild-race-r

Installation impressions: So far they seem ok. Lateral and radial runout is good, they weigh 600 grams each. First glance and they do appear undersized, right at 2 inches but this may be partially due to the narrow Mavic 317 rims which are only 17.4mm wide on the inside.

First ride impressions: Tires roll faster than the Forte Tsali/Pisgah I was riding previously. I ran 30 psi in the rear and 27 psi in the front. This seemed about perfect in the 70 degree weather. Probably going to need to go up a bit in the cold. They feel like they have less absolute grip in the center section, I slipped on a root I’ve never slipped on before. But more grip in the corners. Which is what I wanted, good characteristics for a gravel tire. Tires also expanded every so slightly from 50mm to 52mm.

So I like them, they roll well and handle cornering well. I was getting wheel flex before sidewall collapse so there’s a good combo of tire pressure and sidewall strength.

First Race Update: 2/25/2017: I just got done racing at the Assault on Currahee Mountain, a gravel/dirt road race in the Lake Russell WMA near Cornelia, GA. These tires performed awesome. They are fast on the road, fast and grippy on dirt and gravel and they seem nice and supple at my preferred pressure. Once these wear out I am going for the advance version which should roll a little faster and perhaps be a little grippier?

2017-02-28_9-18-37

Kenda Happy Medium 700×40 Review

Here’s the specs from the company site: http://bicycle.kendatire.com/en-us/find-a-tire/bicycle/cyclocross-gravel/happy-medium-pro/

2017-03-22_9-24-02

These tires are great, the fastest rolling knobby tread tire I’ve used. I plan to do all my flatland gravel racing on these next year.

On road they are obviously slower than a smooth tread tire but they feel fast and are fun to ride. When I did my first shakedown ride I figured it would be like when I rode Small Block 8s or WTB Nanos – fun on dirt but really boring on the road. Not with these tires, I ended up riding for an extra hour and then just riding the bike for the next two weeks. They didn’t have that saggy/boggy feeling a lot of dirt tires have.

Also got me back into monster cross. I’d ride around on the road for an hour in the morning til the trails opened, hit the singletrack for an hour and then go home really satisfied with a fun ride. The tires seemed to handle the rocky, rooty Sope Creek trails just fine. I ran them around 35 psi with tubes for a 200 pound rider/bike weight and had no problem riding hard and fast. Of course, being a steel cyclocross bike the ride was interesting to say the least and overall much slower than an MTB but still very fun.

I also raced two gravel events on the tires. They handled the dry, dusty conditions fine. Rolled fast, cornered well and seemed to be on par with the other riders. I did note that the microknobs on the rear were showing some wear after about 200 road miles+100 gravel miles but I would suspect traction in the dry would not decrease much if they disappear completely. Wet conditions may be another issue but I’ll update if we ever get any rain.

The tires with tubes were ever so slightly undersized on the stock HED Tomcat 25mm width rims. Front and rear were both 39.5 after about 300 miles. So expect them to be a little narrower on narrower rims and maybe up to stated width when run tubeless.

So, overall really good tires I think.

Grand Bois Hetre Long Term Review

6400 miles on the pair. Rear went 4500 or so before a I retired due to thinness of the tread. Rotated the front to the rear and got another 2000 or so miles before a manufacturing wobble gave out. This section of the tire was always out of round so it’s no surprising that’s where it finally failed. Really impressed with the longevity of these tires. Running 700c the most I ever got was about 2500 miles on a pair of tires.

They work and work well, measured true to size at specified psi on my Stans Crest rims. I never felt like they lacked anything in on road performance. They’re kinda shitty in the rain and I think this is a combination of the vertical tread and the rubber compound. The vertical tread seems to allow water to fill the areas between tread bars and the surface tension keeps it in place and reduces the tires contact with the road since a large portion is now filled with water whereas before it was air and rubber. The rubber is just old-tech Panaracer compound, they’re a conservative Japanese company so i wouldn’t expect this to change any time soon. Now to clarify the tires are ok in the rain just don’t expect to be railing any descents with these.

I read a lot about puncture resistance before I started using the tires and my experience for the first 4500 miles was very different than what I read. I had a high number of flats over that mileage span, four due to embedded glass working through the tread over time, one puncture from a nail, one from a razor and one from a radial tire wire. So 8 over 4500 miles, very high for me.

When I rotated my front Hetre to the rear and discarded the old rear I had 0 flats in the 2000 miles I used the tire. What I’ve been thinking is this is a combo of just having a softer tire in the rear that was picking up glass and the front aging into slightly harder rubber and being more resistant. I used to use a headlamp to inspect the rear and remove glass before it worked through to the tube. That never happened when I rotated the front to the rear. That 4500 miles it was on the front gave it some age and hardened it to be slightly more resistant I think. Tire pressure was consistent the whole time. I would pump the rear to around 40 psi, front to slightly above 30 psi and run them until the rear felt unstable in cornering, about 30 psi. Bike and rider weight between 190-210 pounds.

One thing I didn’t like that I haven’t seen addressed was the propensity for the tire to grab onto straight surface artifacts like raised paint lines. This is an issue with any tire with vertical tread features but it was especially pronounced with the Hetres. I almost crashed riding no hands when I drifted onto a thick paint line and the bike wobbled hard as the front tire grabbed the paint and was pushed into a different line. The effect seemed more pronounced with lower pressures and colder weather.

So anyway, good tires. Really happy with them.

img_0787-1img_0788-1

Fucking Compass Tires

“42mm” Babyshoe Pass tire mounted on Stans Crest rim with a tube at 35 PSI.

img_0789
🤔

https://janheine.wordpress.com/2013/05/23/tire-width-how-much-difference-do-a-few-millimeters-make/

And even the difference between a 38 mm tire and a 41 mm tire still is 16%. No wonder the Grand Bois Hetres feel so much more comfortable than the Lierre and Pari-Moto tires, even though they use the same casing.

LOL