soloist_huaxin

First post so please forgive/point out any violations.

Have a 2014 REI/Novara Strada road bike with 105 brakes/Weinmann DPX rim(ETRTO 622x13.4)/25mm tire, mostly used for commuting(has rear rack) and neighborhood rides. Recently a group of friends wants to ride along a local beach's back road which is unpaved, and they are all using hybrids. I wanted to join but am worried that the 25mm road tire may have issues for sandy/gravel road. Here comes my questions:

1. would it be possible to fit 28mm(or even 32mm) tires into my frame/brake/rim combo? Do I need a new wheel(set?)
2. I'm planning on riding more of this kind of mixed roads in the future, but won't be able to buy another bike/change my current bike for a new one, assuming it's possible to fit 28/32mm tires, would it make sense to get a second set of wheels for this "leisure/tour" purpose, and use the 25mm wheelset for everything else? The cost for new wheelset+tires is ~$200, possibly $30 more if I want a separate 10spd cassette on it...

Any idea/insight/suggestion is welcom

Hypno Toad

I think you can get 28mm tires on your bike, I'd recommend going to REI or local bike shop with the bike to check the clearance on your fork and frame. Clearance will be your biggest issue, not the wheels.

I ride 25mm tires on my Felt Z85 (road bike) on limestone trails all the time. I've used these 25mm tires for short duration on gravel roads and other no paved surfaces.

I ride 28mm tires on a couple bikes, Kona Dew Drop (commuter bike) and Globe Daily (city bike). Both ride a lot of non-paved surfaces. I use the Kona for gravel century rides on the same 28mm tires. I use the 700x28c Panaracer T-SERV (this link is the 25c)

The only real issues with narrow tires: traction and comfort. You can minimize these issues with a tire with more traction (CX tires) and ride them at a lower pressure (like 90 psi).

If you will ride on the beach surface, then you need a fatbike - and that is just awesome fun... but I don't think that's what you were looking for.

FBinNY 

The limiting issue isn't the rim, it's the frame, fork and brake clearance.

You can estimate how much wider you can go by looking at the room you have now. Increasing the tire width increases the height by the same amount, and the width by half the amount on each side. So, for example, if you have 5mm under the top of the fork or brake arch, you can go 4mm wider, leaving as little as 1mm clearance there. OTOH that same 5mm wider tire will need 2.5mm more room on each side (usually at the chainstays).

Two caveats.

1- tire nominal widths only approximate the actual width, so your result will vary somewhat depending on the specific tire.
2- while you can work very close radially (height), you need more side clearance to allow for possible wheel wobble.

BTW- here's a link to recommended ratios of tire and rim width. Use it as a guide, but inderstand that there's plenty of fudge room to either side of the "right" fit.

nfmisso

As noted above, wider tires will fit on your current rims.

So you have the bike. MEASURE the gap around your tire at the fork, brakes, chain stays and seat stays.

28mm tires are 3mm taller and 3mm wider than 25mm tires, so above the tire you need room for 3mm more, and 1.5mm on each side.

32mm tires are 7mm taller and 7mm wider than 25mm tires, so above the tire you need room for 7mm more, and 3.5mm on each side.

PLUS there is variation in tires, so add an extra 2mm in every case, because we don't know if your 25mm tires are on the smaller or larger size.

The most important question that needs to be answered is the total weight of you and the bike. If that is light, 25mm tires are probably fine for unpaved stuff, if it is heavy, even 32mm tires may not be sufficient.

Sheldon Brown suggested wider tires in front for off pavement, with tread on the front, slick or semi slick okay on the rear until you get to mud and deep sand.

dsbrantjr

+1 Check everywhere to find out where the tight spot is, both front and rear. On a road bike it could be the brake bridge or chainstay width in the rear, likely the brake in the front but this can vary. I have a hybrid where the front derailleur pivot is the limit for the rear tire.

You can use hex L-wrenches as gauges to estimate how much clearance you've got from your existing tires, but be aware that tire sizes are not consistent; some 28 or 32mm (for example) tires are wider/taller than others. They should be more consistent if you stick with the same brand and model and just go with a larger size.

Hypno Toad

That's a good point that I wasn't thinking about. I run fairly light, me and my bike (Kona) run around 190 lbs.

soloist_huaxin

Thanks everyone for suggestions!
As for weight, I weigh just over 150#, the bike is somewhere around 25#(it's a guestimate, specs say 21ish, add the rack/bag/bottle on top of that), so probably on the light side, which means 25mm might be fine? Is there any 25mm tires with decent tread for more traction? FWIW Currently I'm using 25mm Clement Strada LGG Road, the tire that comes with the bike.

nfmisso

Continental 4 season GP might be a possibility.

dsbrantjr

Check your clearances, treaded tires tend to have taller profiles than slicks; if your clearance is close they may not fit.

soloist_huaxin

That price though...tried ebay, and saw some Schwalbe Marathons, also LBS has Vittoria Zaffiro Pro3, any reviews on those?

Checked last night, height is not as big an issue as width clearance, I should be able to fit an 28mm but that's pretty much it.

Tim_Iowa

This guy fit 35 mm tires on the same bike, so it seems like you'll have plenty of clearance. https://www.bikeforums.net/road-cycli...s-ta-work.html

For gravel, I'd say get the widest you can fit. 28 mm tires should help, but 32 mm tires would float even better. You should use a tire with a light tread, a file tread or basic tread like a Pasela should work.

soloist_huaxin

Could you elaborate on the tread part? I thought slicker tread will slip more on gravel? I was thinking along the "knobbier/MTB-ish" side if there is such a thing on road tires...

Andrew R Stewart 

Unless the road/trail surface is soft enough and smooth enough tread/knobbies won't dig into the surface. Add rocks larger then the gaps of that tread and the road/trail surface will just compact very slightly, kicked away or/and get plowed aside greatly by the tires. Tread won't do much in these conditions. But tread does increase the tire's height/width, given the same casing as a slicker treaded version. Making the tight clearances under calipers/crowns and between stays/blades less for otherwise the same air volume. Andy.

cpach

I looked up your bike, is it this: Novara Strada Bike - 2014 - REI.com ? If so, you actually have medium reach shimano calipers (not actually 105). The real solution is still to measure closely, but I bet you could run narrow cyclocross tires--maybe like a Michelin Mud2 or Jet at 30mm rated width. If for whatever reason you want to get a second wheelset, consider tubeless rims with tubeless cross tires--you'll be able to run low pressures without pinch flatting.

Some other ideas: if you run the widest treadless or relatively lightly treaded road tire you can fit, you may find that it's a great (or better) road tire while allowing you the ability to take it on some mixed terrain. Also, you may just want to try what you've already got. I'd feel OK riding a road tire on most forest service roads, but maybe not very gravely or loose roads. It depends on local conditions. Remember that generally speaking lower tire pressures will handle better offroad until you get to the point of pinch flatting or some other kind of tire failure, or the tire is actually squirming excessively on the rim. Your problem will most certainly be pinch flatting.

caloso

The narrowest CX tire I could find was the Kenda Kwick. They're listed as 30mm but I doubt they're that wide.

Tim_Iowa

The only time you need real knobs is in muddy conditions. For dry gravel, semi-slick is fine so long as it's wide enough for you to float on the surface instead of cutting through.

A semi-slick will roll much faster on pavement than a knobby. For example, compare the Clement LAS to the Clement PDX or MXP. The file tread on the LAS is great for hard surface, whereas the others are more knobby for mud. Clements are excellent tires, btw.

You are light enough, so a 28 mm tire may be wide enough for occasional, small gravel (like a crushed limestone trail). If you can fit a 33 mm tire (I believe you can) then that opens up the wide selection of cyclocross tires, which should all be competent on gravel.

Personally, I'm much heavier (#225) and the gravel around here is quite rough (crushed lime rock, .5-1"), so I prefer at least a 38 mm tire to stay floating on top. My main gravel bike rocks with 60 mm Super Moto tires!