big difference going from 700x32 to 700x40? and pannier stabilization on rough trails
 

I tried out my new Windsor Tourist with its 32c tires on one of the local trails.. admittedly, the trail was in pretty bad shap.. lots of ruts from horse traffic and some roots poking out. I was miserable going down the trail with the 32c tires.. my panniers kept bouncing in the back.. the 32c tires were aired to 80PSI.

The bike will accept up to 40c tire width. Will I observe a significant improvement with 40c tires? Will 40c tires also allow for lower air pressure?

Well, my first thought was rather flippant--just stay off that trail. I just think this because 32c tires should be fine for most riding. 40c tires will be a bit better, but they will also
slow you down a bit as well. Not sure much would be gained by swapping out the 32's for the 40's.

Seriously, the trail seems to be the real problem. It needs maintenance. In the past I have contacted the government agencies that maintain the local trails in my area. Often
they are responsive. Often they are not aware that the trail is in need of repair. So, I would stay with the 32's at 80psi, and ride elsewhere until the trail is in better shape.

I have a Windsor Tourist. I find the 700x32 good for smoother gravel and any paved road but not for trails or washed-out gravel conditions.

I use a 700x38 Schwalbe Marathon Cross for wet or washed-out gravel and trail conditions with good results.

BTW, the 700x38 is a tight fit. I would not want to use a larger sized tire on the Windsor Tourist.

Have a pair of , actually 2 of the 3 Nokian A10 I bought a long time ago, a 622-40.

One casing sidewall burst, in Ayrshire Scotland mid way through a tour
from SW Eire,
probably too much cold weather gear, brought for the Feb -Mar start .. by May,

to Northern Scotland, over 6 months .. had hardly any tread wear I could see..

Not only will they allow for lower tire pressure but they may require it. I've had numerous issues with blow-offs when using tires over 32mm. All of the 35 to 37mm tires I've tried can't be pumped up to more then the rated pressure

It all depends on how big of a load you have on the tires and the shape of the tread. If you need 80psi on a 32mm tire you might get away with 65psi with 38mm but the first thing I'd suggest is getting a long bungie to secure the panniers to the rack so they can't bounce around. The next thing is to get a tire with a wide tread and knobs on the sides like the Marathon Cross or Continental Travel Contact. so it can't skitter around riding on a center tread as is common for street tires.

Common sense suggest bigger tires, lower pressure for a smoother, slower ride. Probably not enough though to make for a comfortable rough trail ride. Need a shocked hybrid with big tires for that.

Ahh I see you're in the area.. the trail I was referring to was the Des Plains River trail, the 5 mile section south of Lake Cook Rd.. holy crap it was bad! I'm planning on doing a short tour up to Zion, IL this summer and i was thinking of taking the DPR trail as far as I can go before cutting East.. I don't have confidence of riding with traffic yet.

Yes, I know it well and have covered the entire trail from Dundee Rd to the Wisconsin border. The section in Cook County is badly maintained, Lake County is very smooth and fast. I would use a better quality 700x35 or 700x37, IMO. Any one of these will do;

Vittotia Randonneur Pro: http://www.vittoria.com/product/city-trekking/

Schwalbe Dureme: http://www.schwalbetires.com/node/2666

Schwalbe Marathon Mondial: http://www.schwalbetires.com/bike_ti...rathon_mondial

Continental Top Contact: http://www.conti-online.com/generato...opcont_en.html

Panaracer T serv PT: http://www.panaracer.com/urban.php

Happy Trails!

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[QUOTE=boogman;13980068]I tried out my new Windsor Tourist with its 32c tires on one of the local trails.... I was miserable going down the trail with the 32c tires.. my panniers kept bouncing in the back.. the 32c tires were aired to 80PSI. [QUOTE]

If 80 was adequate for the rear, you needed less than 70 for the front and less than 60 if you only had rear panniers. That might have made it a bit more pleasant.

FWIW, 40s will let you drop the pressure at least another 20# in each tire. That should smooth things out.

The only way to keep your panniers from bouncing is to stay off that trail or use a bike with shock absorbers.

Thanks for all the tire suggestions!

I thought perhaps my choice of Pannier was bad? I was using Ortlieb rollers.. I've since learned these panniers might only be appropriate for the road, or I will need to rig an additional attachment point to keep it from bouncing..

I just ordered the Nashbar waterproof panniers, those have the bungee attachment, they're suppose to attach the pannier more securely onto the rack..

I rode the same trail the next day with my alu mtb and it was night n' day difference... I think I'll get larger tires for the touring bike...

Barrettscv: When you had the 38c Marathon Crosses, were you able to still fenders?

Well at least I got some pics of the bike from the ride..

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1. get a long bungie that can wrap from the bottom of the rack strut over the sides of the panniers then clip on the rack. 3/16" thick bungie is good because it'll stretch far without crushing things too much. Just be VERY SURE there's no chance the bungie can unhook. Even with a non-rattly pannier the stuff inside the panniers can bounce around.

2. get some electrical tape or gorilla tape to pad out where the clips attach to the rack if the inserts are still too big. Do the same on the rack strut where the bottom hook clips on the rack.

I haven't ridden with the Ortliebs on trails but without all of the above they are much too rattly but even panniers with the pull down type attachment will allow the contents to rattle around.
When I was commuting 11 miles on road and 1mile on trails with some Jandd panniers filled with clothes and a few tools I did the same thing to keep stuff from bouncing around when the bike and I were bouncing around.

The fit with the 38c Marathon Cross with fenders was very tight. I’m OK with tight fitting tires and fenders, but not every user will want to deal with a more difficult installation and the occasional adjustments needed. The first problem was at the chainstays, near the crankset. Each side has less than 4mm of clearance. The Planet Bike Hardcore Hybrid fenders were also a tight fit around the tire. Planet Bike specifies a 700x35 max tire size with these fenders. Fitting a 700x38 tire was a hassle. I would stick to a 700x35 or 700x37.

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I have a pair of 38 WTB Pathways on my SS and they handle all conditions very well. Sadly I can't tell you if they would fit your bike with fenders. I also have some Schwalbe Dureme's, they are also a great all condition tire ...just a bit more$$$

I got the WTB's very cheap on ebay http://www.ebay.com/itm/WTB-Pathway-700c-x-38mm-Cross-Urban-Tires-NEW-/180843120628?pt=Cycling_Parts_Accessories&hash=item2a1b1707f4

Ortleib rack mounts can handle more shaking than any rider can. They should have come with some small plastic shims for narrower rack sections. make sure that the anti-sway hook is positioned to engage the rack struts tightly.
I have ridden steep, rough, rutted, boulder-strewn mountain trails, fully loaded on 32mm tyres and it is very tricky. I often wished that I had 38mm which seems to be the modern standard for touring bikes.

My wife and I use those, and while i like them for their simplicity and light weight, I don't think they'll help much. The bungee is a relatively lightweight elastic strap. and basically just pulls down on the bag so that the hooks do not easily bounce off the rack.

They do have Velcro that wraps around the tube that the hook sits on to avoid bouncing off though.

I's just do something similar to what lee mentioned regarding an added bungee over the bag.

Common sense is often wrong, though. As Jan Heine has shown in a series of articles in Bicycle Quarterly, under real world conditions, wider tires run at lower pressures are just as fast as narrower tires at higher pressures. The ride is smoother, but not necessarily slower, because you're not losing as much energy to vibration. The most important factor is how supple the tire sidewalls are; there's a huge difference in efficiency between different tires of the same size.

+1 The Nashbar panniers I had not only rattled, but would pop off if the velcro tie downs were not fastened. However, they were in the wrong position for my rack, and I could only fasten one. This was very disconcerting when one of the hooks on my front pannier would come unhooked while going downhill. I've never had that problem with Ortliebs.

These are 32mm tires. The road was too muddy to ride on. On our tour last summer part of our route took us over 900 mile of these types of surfaces. My bias is probably starting to show- I'm not a fan of fat tires. 32mm is about as big as I'll go. While rolling resistance may(?) be similar in different sized tires, the weight of wider tires is usually greater. I really noticed the difference when I went to the 32mm form 28mm tires. I'll probably go back to 28mm or at least a lighter tire for next summer's tour, which is mostly on pavement.

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P.S. This is all done on 32mm tires! I know, no panniers:)

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I have Ortlieb Bike Packers and Sport Packers with the QL2 system. I was thinking the same thing about the inserts. I rode a very rough road that was steep in places in MT last summer. It was even bare rock in a few places. While the lower hooks came disengaged a few times, the top connection ones worked flawlessly. The bottom hook problem I can remedy by wrapping the racks with cloth grip tape in a few places.

Bike was fitted with 37c Conti Top Contacts. They worked great.

Hmm! good idea of wrapping the rack with some tape.. because even with the shims for the ortlieb's top hooks, there is still a few mm of room for the pannier to shift around..

I just felt like the panniers were going to break apart from all the shaking!

The inserts for the top hooks work great with my rack. I actually used the smaller ones even though the instructions called for the larger ones. The tape will be for the bottom "hooks." The gap between the inside surface of the hook and the pannier is too wide, and the hooks are too flexible. On rough roads, the bottom hooks end up outside the rack. This mostly happens with the front bags. Wayne from The Touring Store suggested the tape idea.