Sayeth Richard:
I am also planning on putting rear panniers, 40 litres, on the front. I know some people do this and I will make sure that the weight of them will be well within the limits stated by Thorn.
Replyeth Martin:
Other things to check when using large panniers on the front are ground clearance (might be an issue with off-road use) and, more important, make sure that no parts of the bags can flop into the wheel. This is a minor nuisance on the rear, I have had it happen with an old Karrimor rack and old, sagging nylon panniers, but it could be dangerous on the front.
Large, heavy panniers on the front combined with small rear panniers used to be a standard French touring configuration when I arrived in France 30 + years ago, but the racks and panniers were specially designed for the purpose. Thorn and other current low-loader racks seem to be designed specifically for front panniers.
My Ortleib Bike Packer Plus rear panniers will fit on my Thorn low-loader front rack, but I haven't yet used them on the front apart from a short test ride to see if it seemed reasonable (I reckon they would be OK). When ordering my Raven Tour I asked SJS cycles about using rear panniers on the front and they advised fairly strongly not to do it
Richard, there's several issues at play here, and I can speak from firsthand experience and expand a bit on Martin's thoughtful answer, having explored the concept personally on my own Thorns (past Sherpa Mk2, present Nomad Mk2) and another Thorn I've toured with extensively (Raven Tour).
I sometimes have to carry a lot of water (26liters+) for desert touring. At one point, I had thought about placing that water in my rear panniers and moving much of my other cargo to the front by using rear panniers on my front Thorn Low-Loader rack. I had successfully used rear panniers on the front of my previous expedition bike for past trips (and used small panniers on the rear). I pondered the question openly on the Forum, and received a reply from Thorn advising against it for clearance and handling reasons and investigated further.
Here is what I found when I investigated further and actually tried in some trials:
1) My old panniers were made in a landscape format no longer widely available, rather than portrait format as with modern bags, so ground clearance with the old bags was less of an issue when they were mounted on lowrider front racks.
2) With the modern rear bags on the front (In this case, Ortlieb BikePackers instead of the usual smaller SportPackers), curb clearance is reduced to the point where the bags can rub a curb if you are near one and tilt a little. Very little. This can snag a bag and potentially cause a fall. Bridge aprons are generally taller than city curbs and could be a real clearance issue. I scraped holes through the bottom of even my smaller Ortlieb SportPacker Plus front bags when a bus trying to avoid an oncoming car forced me against a bridge apron in Croatia.
3) The taller rear bags can extend higher above the rack, which can cause interference with some downtubes when turning at the sharper angles sometimes required at low speeds. This is especially true if the bags are filled to capacity so the upper part is also full.
4) The rear bags are thicker laterally, so they pack wider. When packed, this effectively reduces the lean angle if mounted to lowrider racks up front. The wider load will contact the ground sooner when leaning into a corner. Remember, the load will not only be lower (thanks to the larger bags), but wider (because they are thicker). Both reduce lean angle. This wide-low thing is also an issue if you are going off-road or on narrow, deeply rutted roads, as the front bags can catch the sides of the ruts. In late May approaching Belgrade, the Eurovelo 6 track lead through unmowed dike-tops and I had a real workout riding through the thigh-deep grass with my smaller SportPackers on the front. I'm not sure I could have pushed the bike through if the larger BikePackers had gone first.
5) Thorns are made with relatively high-trail geometry. This geometry tolerates weight at the rear much better than at the front. Low-trail designs (as on the French Constructeur-inspired bikes Martin references) are much happier with a heavy front load, but there are handling and load-carrying compromises with both. And, as he observes, most current front racks are sized toward carrying smaller panniers. For more on frame geometry and handling, see:
http://www.thorncycles.co.uk/forums/index.php?topic=4245.0For these reasons (clearance and handling) I would suggest *not* putting the bulk of your weight up-front on a Thorn touring bike. This load scheme is best tolerated on bikes made with low-trail geometry as can be found on some classic and current dedicated randonneur bikes, where a large handlebar bag sits low above the front tire and may also be paired with some large front panniers and a token rear load at most. Of course, you may well be able to do this within limits on your Thorn, but it will really handle better with more weight on the rear, as can be seen in Thorn's load charts, created by designer Andy Blance and reproduced in one place for comparison in the new Mega Brochure available here:
http://www.sjscycles.com/thornpdf/THORN_MEGA_BROCHURE.pdfHere are some related Forum links you may find helpful:
• This question has been asked before. Here's one thread with specific ground-clearance measurements:
http://www.thorncycles.co.uk/forums/index.php?topic=4937.msg25361#msg25361• More generally addressed:
http://www.thorncycles.co.uk/forums/index.php?topic=4937.msg25347#msg25347• Relevant thread:
http://www.thorncycles.co.uk/forums/index.php?topic=4937.0• Thread devoted to packing of "big" items:
http://www.thorncycles.co.uk/forums/index.php?topic=1998.0• Thorn Designer Andy Blance's own packing schemes and recommendations for carrying weight, and where:
http://www.thorncycles.co.uk/forums/index.php?topic=4515.0• Heavy front loads on a Thorn, steering stabilizers, and wheel flop:
http://www.thorncycles.co.uk/forums/index.php?topic=10025.0If you can keep the weight within Thorn's recommended limits, then the deciding factor for your using rear panniers on the front will be ground clearance and lean angle. This will vary by pannier brand and model as well as its individual dimensions.
Of course, everyone has their own preferences and way of doing things, and not all gear can be compactly stored. Putting rear bags on the front in this case would work best with light but bulky loads. However, I think if one could get overall volume down to a *maximum* that would fit in 40l rear bags, 30l front bags, a handlebar bag for light but handy items, and a rack-top for a drysack should meet most needs. Handling will always be best if weight is minimized, but weight and bulk are part and parcel of touring. The real question is where and how best to carry it on a given bike considering need, geometry, and conditions.
Hopefully helpful.
Best,
Dan.
