Why front suspension only?

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mobi

Well-Known Member
Location
S E England
What benefit do you get in a front suspension only compared to full suspension and no suspension at all?

Are these bikes called Hardtails?

:biggrin:
 
Why front suspension only?

Dont want to repeat the same mistake twice:biggrin:
 

Landslide

Rare Migrant
Yes, front-suspension-only bikes are commonly referred to as hardtails.

As far as the benefits go, there are a number of factors to consider. Any bike is a trade-off between these factors.

Intended use
For purely on-road use, suspension is largely unnecessary (although those who've sampled the delights of Sheffield's potholes might disagree :biggrin:).
The rider can provide plenty of shock-absorbance through slightly-bent arms and legs without too much of a detrimental effect in terms of rider fatigue.
For serious off-road use over bumpy terrain, suspension allows the wheels to remain in contact with the ground more of the time, thus improving traction (transferring pedal power into motion, braking, steering). In addition, the suspension absorbs a lot of the forces that would otherwise be transmitted to the rider, thus increasing rider fatigue.

Weight
For a given bike (i.e. same frame materials and components), a fully-suspended bike will weigh more than a front-suspension bike, which in turn will weigh more than a fully rigid bike. Whether or not the extra weight is worth it is largely linked to other factors such as better traction and decreased rider fatigue.

Cost
Suspension components cost more than rigid frames/forks (for a given bike). In addition to this, full-suspension bikes tend to have higher R&D costs (compared to rigid bikes, where the traditional double-diamond frame has remained pretty much unchanged for over 100 years). Therefore the addition of suspension either pushes up the price of the complete bike, or the manufacturer will spend less on other components (e.g. wheels, gears) in order to meet the same price point.

There are a lot of other areas for debate (e.g. power transfer) but I reckon these are probably the primary ones to consider when deciding what sort of bike you want.
 

ColinJ

Puzzle game procrastinator!
As wafflycat pointed out, any suspension on most roads would be a waste of energy, and also money. I live on a little cobbled Yorkshire back street and if most roads were still like that I would want suspension on my road bikes.

The energy wastage comes from the tendency for the bike to bob up and down when you pedal standing up, and also from the extra weight you'd have to cart about.

I have a hardtail mountain bike. I chose a hardtail because it was lighter, cheaper, quieter, and more reliable than a full-suspension bike. I bought a mountain bike to get to places that my road bikes couldn't, not for the adrenaline rush so I don't need rear suspension. I can go fast enough downhill on the hardtail to scare myself. If I had full-suspension I'd end up going so fast that I'd absolutely terrify myself. When I crash my hardtail, on a technical descent, I might only be doing 10 mph. On full-suspension, I'd probably be doing 20+ mph when I crashed which would hurt a lot more. I very rarely crash my road bikes, but I probably fall off the MTB a couple of times a year.

My first mountain bike didn't even have suspension forks and I used to get battered on rough terrain. My arms and shoulders used to feel worse than my legs when I got back from long off-road rides.

One concession I've made to extra comfort is to fit a USE suspension seatpost. It's not effective enough to tempt me to exceed my bike-handling capabilities, but it does take the edge off the rough stuff.
 
Whatever design used there is a problem with the chain. When you pedal the chain between the cog and chain wheel is under a lot of tension. This will pulla suspension system up and forward.

This absorbs energy and also means that the bike may "bob" as the pedalling affects the suspension - look at someone riding a "Halfords Special" if you want to see an example...

Rearsusension can work and increase comfort. My Airnimal, Birdy, Brompton and Street MAchine all have rear suspension and improve the ride dramatically
 

jimboalee

New Member
Location
Solihull
+1 on ColinJ.
On a full suspension bike, every time you press on the pedal, some of the energy is wasted compressing a spring.

I don't own a MTB. It may come as a surprise to some that the majority of cyclists in Marin Co. CA ride road bikes. The reason is every bit of land is owned by someone, so going 'off road' is trespass, and some of the 'hicks in the sticks' carry guns over there.
 

jimboalee

New Member
Location
Solihull
PS. Another reason, and the reason it is wise not to picnic in the hills is there are Mountain Lions wild in the woods.

Cannock chase is OK though. You might see the occasional flasher.
 

Mr Creosote

Senior Member
jimboalee said:
+1 on ColinJ.
On a full suspension bike, every time you press on the pedal, some of the energy is wasted compressing a spring.

Not strictly true these days. My Fox shock has three positions "Closed" i.e. locked out and no suspension, "Pro-pedal" which is a position that somehow detects the difference between a pedal push and a rock strike on the rear wheel which means it doesn't bob on a pedal push and is surprisingly effective and fully open which is good for rough descents.
 
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