Author Topic: Touring Recumbent - weight loading between tyres?  (Read 1363 times)

Touring Recumbent - weight loading between tyres?
« on: 10 July, 2018, 01:19:21 pm »
On an upright touring bike you can estimate you load the bike say 60/40 rear to front wheel. Add in weight of pannier loads at front and rear, you might get a reasonable weight loading.

However the touring recumbent is different. With my recumbent there is a lowrider between the wheels which is best loaded with the heavier bags. Then above the rear wheels on a suspended pannier rack are the lighter bags. These AFAIK at more towards the centre.

My question to you good people is whether this changes the front to rear loading ratio from 40/60 that I've read is a commonly used estimate for loading up df touring bikes?

It's probably not important but you vary front and rear tyre pressures according to loading so it is kind of useful to have an approximate guide. Running 35mm/37mm tyres I might use 45/65psi split on an upright for example. On a recumbent could that be nearer a 50/50 ratio say 45/55. So the pressure might be best at 55/60 or 60/65 psi?

You see I'm curious about the loading and it's implications more that the tyre pressure question. I could make the rear bags lighter or heavier to affect this ratio but what is the guidance for recumbents? Suck it and see or are there any established advice out there?

Re: Touring Recumbent - weight loading between tyres?
« Reply #1 on: 10 July, 2018, 02:34:01 pm »
depends where you receive your  er, received wisdom from.

Plenty of people tour happily with rear panniers only. 80:20 weight distribution can result. Tyre pressures can be adjusted accordingly, but in this case it may mean running the front at abnormally low pressures, which is strictly optional...

cheers

Re: Touring Recumbent - weight loading between tyres?
« Reply #2 on: 10 July, 2018, 02:57:10 pm »
You can load it up however you want but assuming there's likely to be a way of packing it to get the best stability and best handling all around. Then how is it different between traditional 4pannier touring solution on a df bike and a 4 pannier system on a recumbent with the lowrider toe of rack under the seat?

Debates on best its probably subjective but obvious differences include recumbent best with heavier bags on lowrider not on rear rack. Your weight is perhaps evenly spread onto front and rear wheels. I just wondered if there is any received wisdom fit this touring solution because I'm not far off do it on my recumbent.

Kim

  • Timelord
    • Fediverse
Re: Touring Recumbent - weight loading between tyres?
« Reply #3 on: 10 July, 2018, 03:30:40 pm »
Load it up and measure the weight on each wheel with some bathroom scales?

When my Streetmachine's fully loaded the balance point (for lifting, not that I can really do it) is somewhere between the wheels, around the base of the seat.  I'm not entirely sure what adding the rider does to that, but I reckon there's a noticable front-wheel bias with rider and no luggage.  YMMV on this one, particularly where body-shape interacts with seat and boom position.

I tend to inflate both tyres to the same pressure (chosen primarily on the basis of the comedy off-roading factor).  They're Marathons and not particularly fussy, and the suspension does much of the work.

(The Red Baron is a rigid racing machine that rarely carries more than a few kilos of rack bag + water[1] and is *extremely* sensitive to tyre pressure on the front:  There's a fine balance between mushy steering and shaking your ankles off on bad roads.  I'm not sure what the actual front/back weight distribution is with the rider on board, I try to avoid limit-of-traction situations on that one :)

The ICE trike has a very lightly loaded rear wheel - without luggage traction can be an issue.  Most of the weight is split between the front wheels, so pressures are lower than a SWB bike.)


[1] I loaded it up with camping kit for racing at the York Rally (the train took most of the strain), and discovered the handling was *scary*.

Re: Touring Recumbent - weight loading between tyres?
« Reply #4 on: 10 July, 2018, 08:49:44 pm »
True enough the suspension takes out most of the road buzz so tyre pressure probably isn't important. Anywhere between a low pressure pinch puncture to a high pressure issues such as sidewall damage. I doubt my old days of 23mm tyres at 110 to 120 psi probably is overkill but I reckon the suspension would take the road buzz out if I was stupid enough to put 23mm tyres at that pressure (not sure the 406 tyres are produced to take those pressures).

My suspension does seem a bit mushy of late. I putting a bit of effort in today and every pedal stroke my front suspension kept dipping. No squat my @rse!

Anyway that's  digression. If I understand you the centre and rear racks tend to even out the loading. Certainly my empty or very lightly loaded (half empty ortlieb pannier) streetmachine balances on the USS bars. I can keep hold of the grips, stand up and pivot the bike around to turn on narrow spaces. Might be difficult with full kit though (buying a 70 litre set of ortlieb panniers so will probably overload with family kit).

LittleWheelsandBig

  • Whimsy Rider
Re: Touring Recumbent - weight loading between tyres?
« Reply #5 on: 10 July, 2018, 09:15:26 pm »
Suspension can't react fast enough to chip-seal buzz to make any difference. It can be quite useful with somewhat bigger but less frequent stuff though. Soft/ flexible sidewall tyres are the only answer for high-frequency buzz. I've enjoyed Moultons for more than a decade and tried a few other suspended road bikes.
Wheel meet again, don't know where, don't know when...

Re: Touring Recumbent - weight loading between tyres?
« Reply #6 on: 12 July, 2018, 04:17:55 pm »
Not sure why you would want to calculate loading split.  While it might average at something like 60:40, that is not a particularly useful figure because, the range for each wheel varies (almost) all the way from 0-100%. 

When you brake hard, especially going downhill, virtually all the weight goes onto the front wheel.  A recumbent might not quite get to 100% but on an upright it is the point where you feel the rear starting to lift off the ground, ie it has no weight on it.

Climbing up a steep hill when seated, virtually all the weight is on the rear.  Here, the front can start to lift off the ground, because it has no weight on it.

Kim

  • Timelord
    • Fediverse
Re: Touring Recumbent - weight loading between tyres?
« Reply #7 on: 12 July, 2018, 04:24:20 pm »
Climbing up a steep hill when seated, virtually all the weight is on the rear.  Here, the front can start to lift off the ground, because it has no weight on it.

While common on uprights, I've never managed to achieve this on a SWB 'bent.  Maybe on a CLWB or something...

Anyway, what you say about the load varying is true on all bikes, but it can still be useful to adjust the tyre pressure according to the steady state for comfort and efficiency.  Weight shifting under braking surely just puts a lower limit on what the pressure should be, but probably lower than a reasonable value to handle vertical acceleration from hitting bumps.

TBH, I think this sort of thing is best arrived at by real-world trial and error.  There's so much you can't easily anticipate.


Re: Touring Recumbent - weight loading between tyres?
« Reply #8 on: 12 July, 2018, 08:10:32 pm »
I have had no problems with wheel lift on my lwb Thorn recumbent even with a heavy load of camping gear on the back .low speed handling on a lwb recumbent
Is much less twitchy than swb recumbent  :)
the slower you go the more you see