STRF, aka suspension type road fork.

[Torvi]

Hey ive been lurking different sites and stuff and it's obvious there is no fork for road bikes that has suspension and modding mtb fork is somewhat pointless so ive came to idea that i dont think that has been seen around and decided to make rough sketch of it.

Basically my idea came from having a pain in the bum cause of all those small potholes that makes our riding quite uncomfortable so ive been sitting and got a sudden bright idea, "hey wouldnt it work out like that?" and started out a sketch just to show my idea. Maybe someone here is engineer and could tell me if such stuff is even possible, would be nice.

Let me explain what are you looking at peeps.

Base fork part is obviously a base fork, nothing to explain here except for it that it will differ from usuall ones, my base forks will have cut in dovetail slides for sliding dovetail joints that are mostly used in carpentry. I will explain why leater.

Springs are supposed to be very tight and rather thin springs, they are meant to move just a copule of mms under load. Reason i want to put there thin springs is because im afraid that under sucha pressure, i wont be able to put thicker ones as they will just break apart.

Movable fork part is a part that is attached ONLY to springs.

Cover is what will be covering our suspension mechanism and keep whole fork together.

How it is supposed to work?

Main idea is that it wont be able to cover big potholes but it will reduce fatigue put on our hands by all those smaller potholes that are everywhere. When Wheel hits a hole, whole force is sent on a spring, that spring will be transferring the force of hit on movable fork part that is attached to it and send it to the upper spring, what will happen then is that susp will make a folding in move that will be just ~3-5 mms, such lenght shouldnt be even felt by us but it will be more than engouh to cover hit force.

You may ask now: But how will it stay together?!

Answer lies in carved dovetail slides in base fork parts, Cover of suspension will do two things, firstly it will hold our fork together and secondly it will guard our suspension from any outer stuff to get in eg water, mud, dust etc that may influence suspension mechanism. Base fork parts will have carved four slides on each side but on different positions and so does cover will have dovetails attached to it so that way it will hold it together and be able to move slightly in order to let suspension work.

But... What for?!

For comfort!

Please share with me your toughs, engineers help will be much appreciated. Thanks.

 

[cyberknight]

spesh roubaix has inserts
trek domane has special fork.
Some flat bar hybrids have sus forks.
TBH though a good bike fit should mean you dont need sus forks , better to ride around pot holes

 

[Torvi]

yes but they cost thousands and my idea is quite more robust which will also apply for a lower price, if possible to make.

 

[ianrauk]

My Ti & Carbon Roubiax bikes has all the comfort that I need, even over pot holed roads..

You are just adding unnecessary weight to a road bike. If people want suspension then they buy mountain bikes.

 

[cyberknight]

yes but they cost thousands and my idea is quite more robust which will also apply for a lower price, if possible to make.

You can get suspension on £300 hybrids sharing the same wheels size as road bikes
http://www.decathlon.co.uk/riverside-300-hybrid-bike-id_8202746.html
http://www.decathlon.co.uk/original-700-hybrid-bike-id_8165505.html
http://www.halfords.com/cycling/bikes/hybrid-bikes/mongoose-crossway-sport-hybrid-bike

 

[Deleted member 23692]

The Lauf 'Trial Racer' leaf spring fork would do the job if they adapted it for a raod bike. It's a simple light design with no moving parts

 

[srw]

If it has no moving parts, how can it give?

To the OP - if you're concerned about a pain in the bum, get a more comfortable saddle (Brooks have built-in suspension because the leather isn't rigid) or a suspension seat-post (Mrs W swears by them on the back of the tandems). If you have a pain in the hands, fit gel handlebar tape.

There's a reason road bikes don't tend to come with suspension - it absorbs and dissipates power and reduces efficiency.

 

[Torvi]

@cyberknight i wanted to keep it as lightest as possible thus this idea.
@Ffoeg this looks mint
@ianrauk i think you miss the perspective as i see it and it's totally fine, my sketch is very crude and it dosent quite show the size i want it to be in reality, thus i make that picture just to show how big/small suspension would be. inside white stripes would be whole mechanism, not big aint it?
@srw i meant pain in the ass that every pothole shaks ur hands, not pain in the bum as it is :P stuff posted by ffoeg is supposed to send impact on those strings and stuff that's why it actually can work.

 

[andrew_s]

susp will make a folding in move that will be just ~3-5 mms

If it's only moving 3 to 5 mm, the far simpler, cheaper, and readily available option is to fit 3 to 5mm larger tyres

 

[Torvi]

If it's only moving 3 to 5 mm, the far simpler, cheaper, and readily available option is to fit 3 to 5mm larger tyres

not quite possible if you have mudguards.

 

[Cyclist33]

If it has no moving parts, how can it give?

To the OP - if you're concerned about a pain in the bum, get a more comfortable saddle (Brooks have built-in suspension because the leather isn't rigid) or a suspension seat-post (Mrs W swears by them on the back of the tandems). If you have a pain in the hands, fit gel handlebar tape.

There's a reason road bikes don't tend to come with suspension - it absorbs and dissipates power and reduces efficiency.

Can I just observe that non-Brooks saddles are also made of materials that aren't rigid?

 

[Cyclist33]

Hey ive been lurking different sites and stuff and it's obvious there is no fork for road bikes that has suspension and modding mtb fork is somewhat pointless so ive came to idea that i dont think that has been seen around and decided to make rough sketch of it.

Basically my idea came from having a pain in the bum cause of all those small potholes that makes our riding quite uncomfortable so ive been sitting and got a sudden bright idea, "hey wouldnt it work out like that?" and started out a sketch just to show my idea. Maybe someone here is engineer and could tell me if such stuff is even possible, would be nice.
View attachment 54599
Let me explain what are you looking at peeps.

Base fork part is obviously a base fork, nothing to explain here except for it that it will differ from usuall ones, my base forks will have cut in dovetail slides for sliding dovetail joints that are mostly used in carpentry. I will explain why leater.

Springs are supposed to be very tight and rather thin springs, they are meant to move just a copule of mms under load. Reason i want to put there thin springs is because im afraid that under sucha pressure, i wont be able to put thicker ones as they will just break apart.

Movable fork part is a part that is attached ONLY to springs.

Cover is what will be covering our suspension mechanism and keep whole fork together.

How it is supposed to work?

Main idea is that it wont be able to cover big potholes but it will reduce fatigue put on our hands by all those smaller potholes that are everywhere. When Wheel hits a hole, whole force is sent on a spring, that spring will be transferring the force of hit on movable fork part that is attached to it and send it to the upper spring, what will happen then is that susp will make a folding in move that will be just ~3-5 mms, such lenght shouldnt be even felt by us but it will be more than engouh to cover hit force.

You may ask now: But how will it stay together?!

Answer lies in carved dovetail slides in base fork parts, Cover of suspension will do two things, firstly it will hold our fork together and secondly it will guard our suspension from any outer stuff to get in eg water, mud, dust etc that may influence suspension mechanism. Base fork parts will have carved four slides on each side but on different positions and so does cover will have dovetails attached to it so that way it will hold it together and be able to move slightly in order to let suspension work.

But... What for?!

For comfort!

Please share with me your toughs, engineers help will be much appreciated. Thanks.

I'm no engineer and you *may* have just invented a revolutionary idea... but I doubt it in all honesty, at most you've just, er, specced up a hybrid bike, and anyway, I'm a bit lost why you would want to focus on front suspension if the pothole-pranging pain is in your butt?

 

[Torvi]

I'm no engineer and you *may* have just invented a revolutionary idea... but I doubt it in all honesty, at most you've just, er, specced up a hybrid bike, and anyway, I'm a bit lost why you would want to focus on front suspension if the pothole-pranging pain is in your butt?

we already have a good way to compensate for bumps for our backs, padded shorts and comfy seats but there is nothing that compensates impacts for our hands, sure we can get gloves but that's just another part of "making life easier" Iam no engeenier myself but once i go carbon fork i will try to convert my stock alu fork into the custom made suspension fork.

There is a one thing @srw said and it's about losing power, how come we will have reduced efficiency if suspension is supposed to come only at front fork and our thursts comes from rear actually? In my opinion by taking some of the impact it will actually make ride more fluent as potholes wont be shaking our bikes so much as without suspension, less shake=less focus on balance=more focus on producing power.

 

[Cyclist33]

we already have a good way to compensate for bumps for our backs, padded shorts and comfy seats but there is nothing that compensates impacts for our hands, sure we can get gloves but that's just another part of "making life easier" Iam no engeenier myself but once i go carbon fork i will try to convert my stock alu fork into the custom made suspension fork.

There is a one thing @srw said and it's about losing power, how come we will have reduced efficiency if suspension is supposed to come only at front fork and our thursts comes from rear actually? In my opinion by taking some of the impact it will actually make ride more fluent as potholes wont be shaking our bikes so much as without suspension, less shake=less focus on balance=more focus on producing power.

Yes but you said in your original post that you were suffering from a sore bum, so I am just wondering why you thought up front suspension as a preventative measure for that, when as you say we already have ways to compensate?

Again, I'm no engineer but as you thrust down on the pedals (as you put it) this pushes your body forward and down so that (I think) some of the kinetic energy that would otherwise transfer to the wheel via an unsprung fork, in a suspension fork is transferred to the spring.

My own experience of riding road vs mountain bikes is that the road bikes (the ones without sprung forks) are a smoother ride because they aren't continually bobbing up and down.

But it does sound rather as if you've already made up your mind that you've nailed this idea, so just get on and do it. I will save time and just slap some fatter tyres on mine.

Stu

 

[adscrim]

Were rockshox not making suspension forks for road bikes decades ago? I'm sure they were used a couple of seasons on the cobbled classic but then carbon came along and the whole suspension for road bikes was dumped - although canyon appear to be playing with the idea

http://www.canyon.com/_en/eurobike2014/mrsc-connected.html