The Project is to have the same bike to perform at Trans Vesubienne, XMB Challenge and 1001 enduro tour.
I need a bike for long ride, very good climber, very good and easy downhiller, and at around 12.5kgs…
Trans Vésubienne is a long technical race in south French Alp, long distance 85Kms, 3700m of climbing, 4500m of downhill.
XMB is a local challenge also in south French Alp, called X mountain Bike challenge, it's Technical Xcountry (not Xcountry for shaved legs ;-)), medium distance 30 - 45Kms on technical terrain.
1001 enduro tour, is enduro race with 3 o 4 stage for a total distance of around 35kms also in French Alp and technical terrain.
For all these practice I imagine a new bike capable of efficiency in a maximum range of use.
First, which wheel size?
I need good rolling over rocks for long ride and agility for enduro and technical terrain, from my experience 29 wheels are very good to roll over rought terrain but agility isn't the best skill of 29er. I prefer the compromise of 650b wheels better rolling than 26 wheels and more agility than 29 wheels, the 650b gives also a very good stability, and a very good grip in devers and on corner.
So wheels are 650b (27.5')!!!
Which suspension travel? And which geometry?
I consider both in the same time, because the skill of the bike for pedalling and climbing is linked to travel and geometry.
To have good capacity for pedalling it's better to limit the travel for long ride 120mm is a maximum but for enduro race 150mm is a minimum, so I choose to have less travel, and oriented the geometry to downhill. Then I choose a rear travel of 130mm and front at 140mm, it's a good compromise for my use so geometry…
Head angle will be slack, 66° at 67°, seat angle around 74° for pedalling, BB at 335mm to 340mm and chainstays at 430mm, seat tube 440mm and top tube 595mm, then the geometry is oriented to go down.
So which Nicolaï platform? Helius TB or ION16? The new ION 16 is very attractive, new bearing, ET Key, lower centre of gravity, and strong and stiff to ride is difficult terrain, with a new kinematic. Helius TB is lighter (500grs better), so no possibility to change geometry, centre of gravity is upper. I choose ION 16 with little modification to be lighter than the series frame, I remove head tube gussets and I use shorter rear shock 200mm instead of 216mm.
So my new frame could be called ION TB or ION 13 a funny play bike for alpine trail!
I would be making contact with Marcel, his ION16 29er is being compared against an ION16 650b wheel size... Like you I am interested in how they compared...
In my mind, it kind of seems that 650b will replace 26 inch wheels and 29er's will be here to stay....
I think I would still stay with a 29er for the races you mention... That is just my opinion. You will know the trails better than I... The only area where by I don't rate a 29er is in the air.... I just cant get it to feel like my Helius FR.... Dam it all.... But that is not the majority of my riding.....
Keep us in the loop as am sure you will with what you decide on
The_Lecht_Rocks: whafe - cheeers - may i offer an official apology for the wagon wheeler "dis-belief"
Sounds cool Cyril, this is what I want the Ion29 for too! I am with Whafe on wheel size, but we are biased. Perhaps also we cheat as we both use a very very light, very stiff carbon wheelset with the Enve's. I cannot describe how much difference this wheelset makes to how the 29er handles and rides through technical terrain.
I understand the question of agility, I approach this by using a short stem, 800mm wide bars and very light stiff wheels. It is still a longer bike of course.
I have always used very big tyres so 650b with a normal 2.2 tyre is very close to most of the 26" wheel bikes I used to ride with 2.4/2.5 tyres on wide AM rims. I don't think I can go back to that after the same 29er wheel with 2.4 tyres!
But for something like Transvesubienne which is very tough, I can see wanting to try and get a very light bike with all that walking and carrying!!
I think you have chosen the right platform in the Ion..
Like Whafe said, if you chat to Marcel, he has built a test Ion29 with even shorter chain stays (440mm) and shorter travel (137mm 216/63) but with the same design,
It has less mud clearance than mine and maybe 2.25 is maximum size rear tyre, but mud clearance is not so much an issue in the South of France! With a 200mm shock I think this would be around 130mm and with a 595mm TT and maybe a 68 HA to keep the agility with a 140mm Pike would make a pretty short and light bike. I would say Under 27lbs...
Marcel is comparing a 650b Ion with the Ion29 I describe so...
Regarding tires, for TransV i ride 29er rocky mountain element BC Edition with 2 Conti tires in 2.2 Then i ride in enduro on 29er i ride my Nicolai with schwalb in 2.35, on my 650b in ride 2.35 or 2.4 tires for enduro, I will make the same on my new bike and 650b with 2.35 or 2.4 is notube so close to 26 inchs.
It's going to be great Cyril. I look forward to seeing it. You always pick interesting colours too, us English are not so brave! I have yet to try the Ion as a pedalling platform but the work on optimising the pivot position and suspension response around a single ring setup can only be good. It stiffens up initially which helps with pedal response I can see.
No Pinion gearbox I see. I am not a fan of the weight increase with Pinion, although I can see some merits.
I was trying to figure out how this could be such a light target weight Cyril..but those tyres weigh nothing! are they strong enough not to tear apart in sharp rocks?
These tyres are very good I ride in hard terrain and rocks so the model is hardskin version in RR rubber the weight is around 800 grs so Michelin tyres looks good to in a version at about 900grs.
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