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05/27/09 |
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| Professional Tweaks, Tips & Reviews By "AJ" Picarello |
| I hope you find my Tweaks and Tips section helpful. If there is something you want to know about, send me an email and I will try to add that to one of my upcoming articles. |
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Occasionally I get to demo high end bicycles. I lucked out when Marin bikes hand delivered me a brand spanking new 2009 Mount Vision 5.8. Much to my surprise, Marin offered up the bike to me for a few weeks! To say I was flattered is an understatement. From the get go Marin knew, with utmost confidence, that I’d love their bike and the Quad Link suspension.
What attracts a buyer to consider purchasing a particular bicycle? In my opinion the look of the bike/ first impressions are most important. I would think the name brand weighs in next, then, I feel that positive reviews certainly help, good warranty, price/value may also seal the deal.
Marin bikes resemble no other suspension design in the industry. Marin takes an unconventional approach to suspension perfection by combining a true four bar link with a high forward pivot. This design creates a bike with a longish swing arm. This look is unconventional and invokes strange and sometimes annoying comments.
Obvious to me, the Mount Vision is an XC bike. With a steep head angle of 69 degrees and 4.7” of rear travel, this bike shouts XC. Funny thing, other riders (even experienced riders) would ask me if I was riding a DH bike. To some, the huge swing arm resembles that of a long travel DH bike. This scenario played out many times in my shop and out on the trail. Some people love the look; others think the frame looks odd and is too bizarre for their liking.
I like the look of this bike. Maybe the DH rider in me could care less how robust the swing arm is. I feel the bike has a well balanced, artist look to it. I can appreciate the attention to detail and I’ve always sided on “form follows function”.
Simply put, the Quad Link suspension does everything a suspension bike is supposed to do. I did not feel one bit of pedal feedback. The suspension is unaffected when braking and remains neutral. Small to medium bumps are gobbled up and the suspension ramps aggressively towards bottom out. Sag is easy to set (and also very important to set properly). The FOX rear shock "Pro Pedal" lever is easy to reach if you choose to use it. I used Pro Pedal on fire roads, but the Marin climbs well even in active mode.
The Mount Vision ride is smooth and the bike is a blast to ride. A bike that inspires me to ride again and again is always a winner in my book. Speaking of suspension, the Marin may be too good for XC riding! As good as the FOX Float works up front, it struggles to keep up with this bikes rear suspension. Some riders may become overly confident in their ability to downhill on this bike. A word to the wise, the Mount Vision will pitch you if you over ride her. The BB height is good for clearing rocks and the head angle is responsive and gives the bike a snappy feel, but these geometry specs are not DH friendly.
Negatives: Well nothing is perfect and I have a couple gripes. For one, the Devo WTB saddle was not comfortable and the edges are sharp. I have more than a few black and blues on the inside of my thighs to support this claim. The WTB grips are too fat and squirmy and they’re not lock on. Under extreme g outs, I could feel some swing arm flex. Please keep in mind that I’m a Pro downhiller and I’m riding down very steep terrain that most XC riders would not ride. I’m also spoiled with my King rear hub and can never get used to a Shimano XT. The XT hub has a lot of play/slop to engage forward momentum.
This bike would completely rule the trails with the rear drop outs (and 12mm Maxel axle kit installed) from the Wolf Ridge (Marin’s 5.5” travel bike). These drop outs will fit the Mount Vision, but you would need a new rear hub that is 135mm x 12mm. Why not slap on a King? With this modification, the Mount Vision would be unstoppable!
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05/24/09 |
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| Professional Tweaks, Tips & Reviews By "AJ" Picarello |
| I hope you find my Tweaks and Tips section helpful. If there is something you want to know about, send me an email and I will try to add that to one of my upcoming articles. |
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I’ve been riding with tubeless mountain bike wheels and tires for the last two years. I have contemplated doing a review on tubeless since I’m still a bit perplexed on whether they’re a worthy upgrade over tube tires or not.
I have to admit that the system does work perfectly fine, but I’ve had some issues over the years. These issues are rather serious and they have me second guessing a positive review. I also wonder if they’re worth the investment or if they’re at all an upgrade over tube tires.
First off let me start with what the advertised, so called, benefits of tubeless systems. Manufacturers will tell you that you can utilize lower tire pressure (for better traction) without the annoyance of getting a pinch/snake bite tube flat. I suppose this statement has some truth to it. Fact is: lowering tire pressure in order to gain traction is something riders will not do for three reasons.
One, running low tire pressure (I assume low pressure for XC is below 30 psi) will dramatically increase your chance of burping air from the tubeless tire/rim bead contact area. Burping will occur if you ride aggressive, blast into turns/berms or jump and land on an off camber. Forget about tire sealant preventing this issue. Tire sealant has not helped my tires hold a bead or has it prevented flats do to punctures.
Second, lower tire pressure is a literal drag to ride. The rolling resistance is very severe and is actually dangerous to ride with either tube or tubeless tires. I’m sure most of you have rode with low pressure before. If not, try lowering your tire pressure and go for a ride. Accept the fact that you’re trying this at your own risk. Most likely, you will scare yourself when the tire flops/rolls from the rim. This unnerving sensation is even more noticeable with single ply tires and skinny rims. Flopping tires are also an issue when running low air pressure on large DH style tires. The skinny is, when your tires roll from the rim, you will temporarily have zero control of your bicycle. I don’t care how good a rider you think you are.
Third reason you’ll never lower your tires air pressure is an obvious one. You have a much better chance of denting the alloy rim with low tire pressure. Not only will your rims suffer possible catastrophic damage, your tubeless tires themselves very often snake bite flat. Yes, straight through the tires rubber casing.
So obviously the advertised ability to safely utilize lower tire pressure with tubeless is a bust. What then are the advantages of tubeless? The only one I can think of is that they eliminate tubes. Without a tube, you will never have another tube style snake bite flat. With tire pressures around or above 30 psi, I have had great success with tubeless!
You will become very aware of how often you run over thorns and also how often you weaken the tires bead when you switch to tubeless. A few companies offer tubeless tire repair kits, but frankly, not one has worked for me (and yes I’ve tried them all). The simple truth is, you must carry a tube with you wherever you go and I also recommend a heavy duty section of rubber for side wall repairs. Some duct tape is also a good idea to keep with you to hold that rubber piece in place when repairing side walls.
A C0 2 cartridge does not have enough volume to blow up a tubeless tire on the trail. A compressor is the only way to fill a tubeless tire with a strong controlled blast of high pressure air. You will need to install a tube during trail side repairs.
I’ve yet to wear a tire out on any of my tubeless tires. I’ve had to replace every tire long before it wore out do to damage to the tire casing, rendering the tire useless (unless I ran a tube). This expensive issue is annoying to say the least.
My tires are always low on pressure before every ride losing up to 15 psi overnight (unless the tire is brand spanking new). Pressure loss is hard to detect and almost impossible to repair if you find the cause. Some pressure loss comes from a loose tubeless valve. This is usually an easy fix, unless you over tighten the external o ring, knurled nut and twist/rip the internal rubber seal. (This happened to me while the bus pulled up to shuttle up to LPS in Moab Utah).
Tubeless tire selection is pretty decent. Many award winning tires are unfortunately only available in tube style, such as Stick e Nevegals. Maxxis offers a wide variety of tubeless tires, but still no mud tubeless tires. I’ve been riding the Maxxis Igniters and they seem very good for east coast conditions. They’re great on rock and hard pack and worked well in Moab and at the Kingdom trails in Vermont. They fall short in slick conditions and I wish they were a bit softer. Maxxis XC tubeless are 70a duro.
I recommend tubeless tires to riders who are competitive. Many a race has been lost due to a tube pinch flat. Riders who have a fat wallet and a lot of patience are also good candidates for tubeless. Weekend warriors should stay clear of tubeless. I feel that most riders will suffer with problems with tubeless. Tube systems work pretty well and are pretty easy to work on trail side.
In the long run, most riders will end up running tubes in the tubeless tires. I’ve battled the tubeless system tooth and nail. As of now, I have a leaky tubeless Igniter on the front of my bike and a Cross Mark on the rear with a tube since the tires bead is weak, not enough to bulge the tube, but just enough to leak all the air if set up tubeless.
In other words, I’ve been beaten by tubeless tires. I have surrendered, forced to run tubes inside this sophisticated, brilliantly engineered, tubeless work of art.
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05/16/09 |
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