Biggest tires possible on a S30?

[IyhelM]

Hi there,
I’m currently riding a 1st gen Vendetta, I’m very happy with it except for the very limited tire clearance (especially in the front) and inability to mount mudguards: roads around my place get very dirty in winter and I have to revert to my Azub trike; don’t get me wrong, I love my trike but obviously my average speed is not exactly the same
So, I have this opportunity to acquire a used S30 (or 3.0, not sure about the nomenclature… the one with the round hole in the back fin) in very good shape, with disk brakes which would allow for easy wheel swap. I have skimmed a good part of the forum but could not get quite a definitive answer: what would be the widest tires one could get with 24" or 26" rims?

 

[JerseyJim]

I'm not sure about 24" or 26" wheels but a post in this thread says they run 32 mm wide with 650b rims.

Brand New - Cruzbike S30 - $3,200 -sold

I don't have much to say in this ad other than this is a fully untouched, still in the bags it was wrapped in, S30 frameset. It's a 2016. I searched forever for this unicorn, ended up finding this and a pristine V20 demo. Bought both, absolutely love the V20, and now have no use for the S30...

forum.cruzbike.com

650b/c rims are pretty close to 26" in diameter so I would think that would be the limit for 26" rims too. The front fork stays narrow and then flares out to clear the cassette, so there's not too much space to play with between the fork blades. Even with 24" rims, there might not be that much more space.

On this page you'll see a picture of an S30 with a Schwalbe Kojak in the back and a different front tire with a fender fitted up front. I can't tell exactly what size they are. The notes say the wheels are 650b. As far as I know the Kojak only comes in 35 mm for 650b.

 

[CruzinCambridge]

Nice sleuthing @JerseyJim. I could measure my S30 if you want... but I'd agree it's going to be tough to fit more than a 35mm in front or rear... maybe a 38mm if you can find one. The S30 was designed to accommodate either disc or rim brakes so the forks aren't as wide as disc-specific bikes, even accounting for depth. On the question of fenders, the bolt hole on the fork crown makes a good place to mount a fender, but it takes a lot of dremeling and filing to get it to fit. I'm impressed this 650b was able to get a full fender in the front... though it looks like it took some duct tape. I struggled to get a half fender (fork back) on. With the angle of the fork I wasn't able to get any of the fancy German models to work. Instead I went with a Planet Bike cheap one and adapted it by sawing it in half and attaching it at the fork crown and with some big P-clamps.

 

[IyhelM]

Thanks guys for your insights.
From what I gathered on the FB Cruzbike group, it seems that with 26" rims one could go up to 38-40 mm which is already more than I was hoping for.
I’ll get the bike next week, I’ll do some trials and let you know.

 

[IyhelM]

Got hold of the Silvio yesterday and I did some quick trials this morning.
As you can see on the first pictures, it came with 28-622 tires which are clearly the upper limit with 622 rims. Looks like the fork was filed already to give a bit more of clearance. Surprisingly there’s actually less clearance at the back, because of the rim brake mount.
So I picked some 26" wheels from an old bike with rather fat tires tried them on and, lo and behold, it squeezes in just fine - we’ll as long as you don’t try to actually turn the wheels
These are 44-559 so I reckon 40-559 would work perfectly.
I don’t have 584 rims on hand but I suspect one could go up to 38-584 - I’ll try to find some next week.

To summarise, max tire size on a Silvio 2.2 is:
* 28-622
* 38-584 (to be checked)
* 40-559

 

[JerseyJim]

Got hold of the Silvio yesterday and I did some quick trials this morning.
As you can see on the first pictures, it came with 28-622 tires which are clearly the upper limit with 622 rims. Looks like the fork was filed already to give a bit more of clearance. Surprisingly there’s actually less clearance at the back, because of the rim brake mount.
So I picked some 26" wheels from an old bike with rather fat tires tried them on and, lo and behold, it squeezes in just fine - we’ll as long as you don’t try to actually turn the wheels
These are 44-559 so I reckon 40-559 would work perfectly.
I don’t have 584 rims on hand but I suspect one could go up to 38-584 - I’ll try to find some next week.

To summarise, max tire size on a Silvio 2.2 is:
* 28-622
* 38-584 (to be checked)
* 40-559

I've been running 1.5" wide tires on the T50 (Panaracer T-Serv 37-559) for comfort. I would imagine 35mm-38mm wide tires would be plenty wide for grip on loose surfaces. I've not had any problem on gravel bike paths with those. I'd probably go toward the 35 mm end of the range as it looks like there isn't much clearance for mud.

It looks like you have the curved slider on the Silvio and it's keeping the handlebars in a good place. May I ask your height?

 

[IyhelM]

Due to lack of choice I’ll probably go for 35-584 CX or gravel tires and as you said it will leave clearance for mud.
I’m 5’11. Compared to the configuration seen on the picture I need to push forward the handlebar a little bit more, I still have clearance from my thighs and my arms still feel to much bent; I need to adjust the handlebar angle, cannot find a good resting position as it is. When I have time, I think I’ll switch back to the original bullhorn bar, I got it with the bike as well.

 

[JerseyJim]

I’m 5’11. Compared to the configuration seen on the picture I need to push forward the handlebar a little bit more, I still have clearance from my thighs and my arms still feel to much bent; I need to adjust the handlebar angle, cannot find a good resting position as it is. When I have time, I think I’ll switch back to the original bullhorn bar, I got it with the bike as well.

OK, you're tall. I'm 5'7". That setup would probably work for me but I'll bet you'd have better luck with the straight slider. That would bring the bars closer to your shoulder height and if you wanted to push it further away it wouldn't interfere with your thighs. With the curved slider you'll probably hit your thighs sooner as you push the bars forward. I can see the bullhorns solving that problem too.

Although we don't have a standard fit for Cruzbikes, it seems like a comfortable and aero arm position has the hands just below shoulder height or at least within a fist width below the shoulder. When people go too high or too low they tend to complain about something not feeling right.

Have you tried flipping the slider and then pushing it forward? That might get you where you want to be. It'll start out much higher than it is now, but when you push it forward you'll be able to get it to the same height but with more arm reach and leg clearance.

 

[IyhelM]

I don’t think I’ll need to flip the slider, I still have some room to push the handlebars a good 5 cm forward, that plus switching back to bullhorns should make for a good arm position for me; it will also put the bar end shifters in a proper position, right now I hate it!
I rode 50 km this morning including a few km of gravel, I’m quite happy with the general handling of bike, I just need some time for this type of adjustments (plus attaching frame bags under the seat, trying 650b rims, building 650b or 26" wheels with a dynamo hub, installing lights, trying fenders, finding shorter cranks, etc.) - but it will have to wait for next week.

 

[IyhelM]

To summarise, max tire size on a Silvio 2.2 is:
* 28-622
* 38-584 (to be checked)
* 40-559

Update after mounting 25-584 rims:
* 28-622
* 35-584
* 40-559

38-584 won’t fit at the back; with 35 mm tires (G-One Allround) it barely fits. And with thinner rims I reckon it would be worse. 38 would probably fit between the front forks but there isn’t much choice for CX or gravel tyres in this dimension anyway.

I’ve been fighting with the hub derailleur over the weekend so I still haven’t test ridden the 650b wheels but I suspect with only 45-50 psi and 35 mm width it should be perfectly smooth