Doomrider74

A few weeks ago I bought a new road bike, Spesh Tarmac SL6 Sport, after not having one since I moved to Canada 3 years ago.

It came with Spesh Turbo Pro 26mm tires, which seem pretty decent: However, I've been reading about wider tires and lower pressures being the way to go these days, particularly improved rolling resistance.

Ive been looking and can get some 28mm Conti GP5000s for around the same weight as the Spesh tires (I was an avid GP4000S user on my old bike). The rims are DTSwiss R470, which can take up 40mm tires, I believe.

I would describe myself as a climber, largely because that's what I enjoy, not because I'm any good at it ( PR for the Alpe du Zwift is 58:50 ). Is it worth swapping to wider tires?

billridesbikes

Ride the 26mm for a few months or a season. If you're getting fatigued easily then maybe wider tires at lower pressure will help especially if you have a lot of chip-sealed or poor roads where you live. Rolling resistance is only better over 'non-ideal' surfaces for lower pressure wider tires. If you're going to ride gravel or you have poor roads the better wider tires will feel. If you have wonderful tarmac the difference will be less, probably not really noticeable between 26mm and 28mm so my vote would be to save your money.

WhyFi

It's worth trying for yourself.

I do love a good hand-wringing session, but I don't understand it with regards to something like moving up or down one tire size. The difference isn't going to be world-shattering, either way. If you like them a little more - good, keep buying them. If you like them a little less, it's not going to be so bad that you won't get your miles out of them - ride 'em to the cords and get something else in a few months.

Edited to add: the other thing to keep in mind is that this isn't necessarily going to result in a wider, more voluminous tire - you're moving from one brand to another so the inflated width could even be slightly narrower (current generation tires, like the GP5k, tend to be a little narrower than those of the same nominal size a generation or two older).

Doomrider74

Yeah, thats true. I know mountain bike tires vary greatly between manufacturers, so I suppose it's fair to say the same about road ones, although the narrower width would suggest the differences are smaller than with mtb tires.

The roads here in BC aren't the best, but not as bad as where I'm from in the UK (I used 23-25mm tires there). TBH I haven't had any issues with the surfaces I've ridden the Tarmac on yet (its a very comfy bike). There was a section I chose not to ride down because it was badly chewed up, but that was also partly due to it getting late in the day and the weather closing in.

With GP5000s coming in a 90 bucks each I'll probably save it until the Spesh tires need replacing.

msu2001la

I didn't really notice much difference going from 25mm to 28mm. I did notice more of a difference going from 28mm to 32mm and things got even better when I ditched the tubes.
32mm tubeless GP5k's are pretty awesome.

My next tire purchase will be some Rene Herse Stampede Pass (32mm) or possibly even Bon Jon Pass (35mm).

Iride01 

The Tarmac I bought new last year had 26mm Turbo Cotton's on it. For a low thread count tire they rode really nice. However I got two punctures on them in less than 500 miles and put my 25 mm Conti GP 5000's on the bike and have been puncture free for over 3000 miles.

Now I'm probably doomed to flat on my ride tomorrow.

But I'd still run them till you either wore them out or got frustrated with them. Gather some data too. What PSI seems to feel the best to your legs and what does your actual data say?

You can get too narrow a tire and you can get too wide a tire. But there are many widths in between that will be plenty comfortable or fast.

Elvo

Went from 25mm @ 85 psi to 35mm @ 40 psi, comfort level is night and day and it doesn't seem to take a significant increase in effort. But I don't have any objective data on the last part.

Sy Reene

If I revisit threads from eg. 5-6 years ago, I don't see a lot of threads mentioning being uncomfortable because of tire pressure. Why is this?

WhyFi

Depends. What answer are you fishing for?

Sy Reene

There was no question. However, just an observation that there seem to be a lot more recency of threads of people seeking more comfort on their rides than there ever was in the past on these boards. It could be the general aging of the bicycling population I suppose.

Doomrider74

I never mentioned anything about needing more comfort.

bOsscO

Short answer; trends...and comfort.
Doomrider74 where abouts are you in BC? I'm in New Westminster.

Doomrider74

Howdy, neighbor. I'm in Coquitlam.

Sy Reene

No you didn't; the first reply referenced fatiguing though. You referenced lower rolling resistance, though of course a tradeoff on aero and weight to some degree. Are you looking for an overall performance increase with all factors considered?

WhyFi

Oh?

Yeah, aging populations are known for embracing new technology and trends.

dmanthree

I rode those tires for a season since they came on my bike. Not bad at all, really, and not worth scrapping for wider tires until they're worn. I'm riding 28s now and feel no need for a wider tire.

Sy Reene

Depends on the hobby. Are wider tires new technology?

I would be interested if there's some resource, eg. similar to a tire inflation calculator type, that could tell one how a combo of rider weight, tire width, tire weight, PSI, for a given speed and/or terrain type would be optimal or sub-optimal. These queries, discussions and arguments recur from time to time, but at the same time these factors should be measurable and be able to translated to objective conclusions. I know a 23mm tire isn't usually the answer, nor does it mean that a 38mm tire is. Somewhere in-between lies the answer for most people (for road riding), but why hasn't someone come up with the means to determine ad hoc?

Doomrider74

One of the wheel or tire manufacturers does this: I can't remember which one, though. GCN mentioned it in a video on YT.

WhyFi

Are they not?

42

Sy Reene

Thanks for all the fish

Doomrider74

Maybe not the tires themselves, but now frames are disc specific, and many don't have a bridge between the seatstays, the frames can now accommodate tires that wouldn't have fitted before.

WhyFi

Zipp/SRAM has a tire pressure calculator - you input your data and it spits out a pressure recommendation. What he's looking for is an optimized tire width *and* tire pressure recommendation that takes in several factors but still leaves out a bunch, which doesn't make a whole lot of sense.

Sy Reene

Aside from the fatigue factor, what is left out and can't be at least pretty predictable? Or at least more substantive than calling it a trend?

WhyFi

How fast is a cyclist?

Sy Reene

That would be one of the calculator entries. Take the Zipp PSI calculator, mix it a bit with the Silca one (which adds more terrain detail options, as well as ability/speed options). Instead of just returning tire PSI, it would return this as well as an optimum tire and rim width. Of course it wouldn't be perfect (it would have to use average values for tire or wheel weights etc), but none of the calculators are, but shouldn't something like this be constructable?