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MTB Setup
My old Giant Iguana hardtail has served me well doing many multi day XC rides but is now getting a bit tired(no disc brakes). I want to set up my barely used 07 Giant Trance 1 dually so it feels similar to my old bike.
On the last major ride on my Trance between Pickering Brook and Dwellingup the front wheel kept skating off the track unexpectantly when descending in pea gravel.
The panniers weighed about 12kg and I am unsure if my weight (78kg) was too far back or forward on the bike to cause this steering problem.
I have never had issues descending in pea gravel with my hardtail.
The tyres on the Trance were Maxis Ignitor 2.1 on the front and Maxis Larsen 2.0 on the rear at about 40PSI.
I have lowered the headset stack height and lengthened the stem from 90mm to 110mm. I also inverted the stem in an effort to lower the handlebars because I felt very upright.
Although I have set the seat and handlebar height identical on both bikes the SAG on my Trance will reduce the offset.
I heard that the RP2 rear shock could be locked when carrying panniers to make it more like a hardtail.
Would this make it handle better when I carry gear in panniers?
Any suggestions how I can improve my setup?
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Do you adjust your shock pressure to account for the extra weight? I suppose it would be more difficult to match suspension performance with the rear carrying a much higher sprung weight, and the rear weight bias of pannier and bob trailer?
The Bob trailer attaches to the rear axle, so is unsprung weight. Should be no impact on shock pressures required unless carrying extra weight on the rider or has panniers on a seatpost rack. Damping, on the other hand, would possibly need to be increased, most likely rebound.
As to the handing difference, are you carrying more / less weight than usual in the trailer compared to what you used to tow with the hardtail? Is the weight distribution changed - more at the front or back?
Remembered from family holidays towing vans and boats, the cars would always push a bit (understeer) on corner entry, but with the load on we never got going fast enough for it to put us at any real risk. Occasionally a bit of sway from the van but the towbar stabilizer bars would damp that.
Haven't done it with a bike, but would like to give it a go. I hear Munda Biddi is a great ride.
Edit: just re-read the post. My comments above are based solely on what's in the photo. ie, no panniers (at least not on the bike) and load is trailer only. When you say you're carrying 12kg in panniers, are they on the bike or in the Bob? If you've gone from bike-mounted to trailer mounted, it would not surprise me that you're experiencing handling differences.
Seatpost height should always be set relative to pedals, not to ground. Example: I have the same length cranks and the same pedals on all my bikes, so when a new one joins the stable, I set the seat height at 74.0cm from the centre of the crank spindle, measured with a spirit level on the top of the saddle. This gets me to pretty much the same pedalling action on all my bikes.
Setting seat height relative to ground (if this is what your're doing - not sure
) will leave your saddle too low. Not only will the bike sag, but duallies tend to have higher bottom brackets to start with.
The RP2 platform (not lockout, thank heavens) will stiffen the shock and make it more hardtail-like for better climbing. I've had shocks with solid lockouts and they tended to bounce slightly. Irritating. The platform still allows the tyre to deal with some unevenness in the trail surface. for better grip.
Maybe lower your tyre pressures if the trail is relatively smooth apart from the gravel. 40psi is high for your weight (which is the same as mine). Say 35psi? I run tubeless, but that should work with those tyres unless the trail gets rocky or rooty, when pinch-flats become a risk.
Weight forward steers better, but at a higher risk of the rider arriving at the next obstacle ahead of the bike.
Sorry the picture of the Trance with Bob trailer not relevant as I would only use panniers when I don't tow the Bob.
The Bob works great except can be difficult over rough or very hilly terrain. I always tend to carry a bit more weight on the Bob because it is easy to do.(up to max.50kg)
Hawkeye you were right about my seat height. I was sitting about 30mm too low. The pressure and rebound on both shocks were also too low which probably affected the downhill handling in gravel.
Tyre pressures were probably a bit high and I will experiment with lower pressures.
The Munda Biddi is a good ride and though not always technical you can ride uninterrupted from Mundaring to Manjimup a distance of about 600kms!
Next year the trail should be completed all the way to Albany thanks to a
$3 million grant from the Federal government "Royalties for Regions" scheme.
Lonely Planet published the Munda Biddi Trail in the top 10 trails in the world.
I'm glad to have your expert validation, Hawkeye, that after 20+ years as an engineer and 13 years as an amateur chassis mechanic on open wheeled race cars I can analyse a rider report (driver feedback), and do know my arse from my elbow. Cheers!
@ Hed, kudos to the loaded off/back road touring. I'm planning to set my next bike up for a bit of MTB bikepacking. The frame is kitted out with rack mounts and I can get "off the rack" soft bags to attach to the fork. The bike's fully rigid with very short trail on the fork so will be interesting to see how it handles loaded. I'm looking forward to getting a bit further into the great beyond self sufficiently.
What are the trails like through the Midgegoroo national park? Do you ride only fire trail or is there a bit of singletrack to keep you interested.
Do you have a route of the trails you followed?
@slowpup, apologies, didn't mean to be disparaging.
PM sent.
Slowpup, when I go MTB touring I stick to the Munda Biddi Trail. With gear on our bikes we only do 15-18 kph depending on the terrain so not much fun on technical stuff. When we reach a hut in the evening we are usually a bit tired and hungry to explore other trails. Probably also a bit scared of breaking our bike in the bush.
Sometimes if we finish a ride at Dwellingup we will take the panniers off for a decent ride on the single track at Marinup.
I use an Old Man Mountain "Cold Springs" rack on the rear of my Trance held on the stays with P clamps. The rack is very strong because most of the weight is supported by the skewer.
Thanks for the heads up on the OMM rack. I hadn't come across them before.
The Cold Springs looks like the solution for my steed. With deeply shrouded drop outs I'm glad I took the option of getting eyelets tigged on.
Hopefully I can find some good epics out this side of the country. You Westralians are blessed in a lot of ways, and it would surpise me not if you took up Wayne Swan's offer to seceed (?SP).